Malcolm Bell - Academia.edu (original) (raw)
Papers by Malcolm Bell
Investigative Radiology, 1990
The authors examined the utility of cine computerized tomography (CT) for noninvasive determinati... more The authors examined the utility of cine computerized tomography (CT) for noninvasive determination of whole kidney, cortical, and medullary volumes. The right kidneys of 14 anesthetized dogs were scanned after an intravenous bolus injection of iohexol, and their volumes determined after boundary identification. After the scans, the kidneys were excised at postmortem examination and their volumes determined by fluid displacement. The mean (+/- standard error of the mean [SEM]) postmortem and in vivo renal volumes were 66.1 +/- 2.2 cc and 78.2 +/- 2.4 cc, respectively (r = 0.86; P less than 0.001). The difference was consistent with the blood, filtrate, and urine contents of the in vivo kidney. The in vivo cortical and medullary volumes correlated poorly with their postmortem volumes because of difficulties in boundary definition. These results demonstrate the feasibility for fast and reliable in vivo whole kidney volume quantitation by cine CT.
Journal of The American College of Cardiology, 1998
A Schmermund, BJ Rensing, PF Sheedy, MR Bell, and JA Rumberger segmental analysis of coronary art... more A Schmermund, BJ Rensing, PF Sheedy, MR Bell, and JA Rumberger segmental analysis of coronary artery stenoses Intravenous electron-beam computed tomographic coronary angiography for This information is current as of December 29, 2011 http://content.onlinejacc.org on the World Wide Web at:
American Journal of Medicine, 2000
Elderly patients, especially those 80 years of age and older, have been excluded from most studie... more Elderly patients, especially those 80 years of age and older, have been excluded from most studies of thrombolysis or primary coronary angioplasty in patients with acute myocardial infarction. We compared the outcomes of elderly patients who underwent coronary angioplasty with the outcomes of younger patients and determined whether there were any temporal trends in survival. We reviewed the outcomes of 1,597 consecutive patients who underwent primary coronary angioplasty between 1979 and 1997, including 127 patients who were 80 years of age or older (mean [+/-SD] age, 83 +/- 3 years, 47% male). Their in-hospital and long-term outcomes were compared with those of 524 patients who were 70 to 79 years old, 527 patients who were 60 to 69 years old, and 419 patients who were 50 to 59 years old. The oldest group of patients was divided into two groups, based on whether they had intervention through the end of 1993 (n = 56) or between 1994 and 1997 (n = 71). The survival rate of the patients who had no complications and left the hospital was compared with expected survival based on age- and sex-adjusted data. Patients 80 years of age or older had more adverse baseline characteristics, including risk factors and comorbid conditions, than the younger patients. The clinical success rate of primary angioplasty in this group was lower than those in the other three groups (61% versus 74% in those aged 70 to 79 years, 73% in those aged 60 to 69 years, and 81% in those aged 50 to 59 years, P < 0.001). The in-hospital mortality rate among patients 80 years of age or older was significantly greater than among patients in the other three groups (21% in those aged 80 years or older, 13% in those aged 70 to 79 years, 9% in those aged 60 to 69 years, and 4% in those aged 50 to 59 years, P < 0.001 ). The clinical success rate of the angioplasty improved significantly in the more recent period (75% versus 45%, P = 0.0006) and in-hospital mortality declined (16% versus 29%, P = 0.07). During follow-up, mortality in the oldest age group in whom angioplasty was successful was significantly greater than in the three younger groups, but was similar to the expected survival in the general US population. The mortality associated with primary angioplasty for acute myocardial infarction in octogenarians remains high, although there has been significant improvement in the clinical success rate. The long-term prognosis following a successful angioplasty is not different from that in an age- and sex-adjusted U.S. white population.
Catheterization and Cardiovascular Diagnosis, 1997
We describe a method of validation of computerized quantitative coronary arteriography and report... more We describe a method of validation of computerized quantitative coronary arteriography and report the results of a new UNIX-based quantitative coronary arteriography software program developed for rapid on-line (digital) and off-line (digital or cinefilm) analysis. The UNIX operating system is widely available in computer systems using very fast processors and has excellent graphics capabilities. The system is potentially compatible with any cardiac digital x-ray system for on-line analysis and has been designed to incorporate an integrated database, have on-line and immediate recall capabilities, and provide digital access to all data. The accuracy (mean signed differences of the observed minus the true dimensions) and precision (pooled standard deviations of the measurements) of the program were determined x-ray vessel phantoms. Intra- and interobserver variabilities were assessed from in vivo studies during routine clinical coronary arteriography. Precision from the x-ray phantom studies (6-In. field of view) for digital images was 0.066 mm and for digitized cine images was 0.060 mm. Accuracy was 0.076 mm (overestimation) for digital images compared to 0.008 mm for digitized cine images. Diagnostic coronary catheters were also used for calibration; accuracy.varied according to size of catheter and whether or not they were filled with iodinated contrast. Intra- and interobserver variabilities were excellent and indicated that coronary lesion measurements were relatively user-independent. Thus, this easy to use and very fast UNIX based program appears to be robust with optimal accuracy and precision for clinical and research applications.
American Heart Journal, 2000
ment of intracoronary stents, other new devices, and recently developed adjunctive pharmacologic ... more ment of intracoronary stents, other new devices, and recently developed adjunctive pharmacologic therapies.
Journal of The American College of Cardiology, 2002
Our goals were to identify clinical and angiographic risk factors associated with major cardiovas... more Our goals were to identify clinical and angiographic risk factors associated with major cardiovascular complications of percutaneous coronary intervention (PCI) (in-hospital death, Q-wave myocardial infarction, urgent or emergent coronary artery bypass surgery and stroke) and to construct a simple score for risk stratification. Both clinical and angiographic features influence risk of PCIs. Percutaneous coronary interventions performed between January 1, 1996, and December 31, 1999, were analyzed. Logistic regression and bootstrap methods were used to create an integer risk score for estimating the risk of procedural complications using baseline, angiographic and procedural characteristics. The risk score was tested in a validation-set consisting of all procedures performed in the year 2000. Among 5,463 procedures, 5 clinical and 3 angiographic variables were significantly correlated with procedural complications: cardiogenic shock, left main coronary artery disease, severe renal disease, urgent or emergent procedure, congestive heart failure class III or higher, thrombus, multivessel disease and older age. In the validation-set, the model fitted the data adequately; the average receiver operating characteristic curve area was 0.782 (standard deviation, 0.018). Eight variables were combined into a convenient bedside risk scoring system that estimates the risk of complications after PCIs.
Journal of The American College of Cardiology, 1999
The aim of this study was to accurately assess the radiation exposure received by patients during... more The aim of this study was to accurately assess the radiation exposure received by patients during cardiac catheterization in a large sample representative of the current state of practice in cardiac angiography.
Journal of The American College of Cardiology, 1990
Percutaneous t emerged as an luminal coronary an coronary artery disease; its use in patients wit... more Percutaneous t emerged as an luminal coronary an coronary artery disease; its use in patients with multivessel disease has resulted in high initial success rates incidence of complications (1-9). The long-term coronary angioplasty in these patients with multivessel disease remains controversial (HI,1 I) and is now the subject of several randomized trials. In particular, the consequence of incomplete revasculariz has become an important issue. Previous studies of nts with multivessel disease in whom revascularization with either angioplasty (2,4,12,13) : David R. Holmes, Jr.. MD. Mayo Clinic. 200 First Street SW, Rochester. Minnesota 55905. or surgery (14-N) was incom ave generally, but not always (tg), shown poorer sy atic outcome and survival compared with findings in patients in whom complete revascularization was achieved. Complete revascu~arizatio~ with coronary angio may not be achieved in patients with multivessel dise a variety of reasons including the presence of an occlusion or lesions either unsuitable ilate. The iong-term outco ted by these and other related v ree of revascu~arizat~o~ acbiev ous Tra~s~uminai Coronary Angioplasty onstrated that differences in ~~~~-terrn completely and into pletely revascularize multivessel disease could be explained largely in baseline patient characteristics (19).
American Journal of Cardiology, 1999
In patients receiving coronary stents treated with aspirin and coumadin, the peak incidence of st... more In patients receiving coronary stents treated with aspirin and coumadin, the peak incidence of stent thrombosis occurs on the fifth and sixth days following the implantation procedure. Little is known about the timing of stent thrombosis in patients treated with aspirin and ticlopidine. We compared the timing of coronary stent thrombosis in patients treated with ticlopidine and aspirin with the timing in those receiving coumadin and aspirin. A retrospective databank analysis was performed and 39 patients were identified who experienced stent thrombosis after successful coronary stent implantation. Of these, 21 had been treated with ticlopidine and aspirin and 18 with coumadin and aspirin therapy. The median time from stent implantation to stent thrombosis in the ticlopidine and aspirin group was 12 hours (interquartile range 6 to 72 hours) compared with 4 days in the coumadin and aspirin group (interquartile range 21 to 68 hours) (p <0.0001). There was no significant difference between the timing of stent thrombosis in patients treated with abciximab in addition to ticlopidine and aspirin (median 17 hours, interquartile range 6 to 29) versus ticlopidine and aspirin patients who did not receive abciximab (median 11 hours, interquartile range 9 to 12, p = 0.57). Thus, in patients who receive coronary stents, stent thrombosis occurs much earlier after the procedure in patients treated with ticlopidine and aspirin than in patients treated with anticoagulation therapy.
International Journal of Cardiovascular Imaging, 2001
New therapeutic strategies in interventional cardiology and electrophysiology involve the coronar... more New therapeutic strategies in interventional cardiology and electrophysiology involve the coronary veins. This study examines the potential usefulness of electron beam computed tomography to obtain detailed noninvasive definition of the coronary venous anatomy and of arteriovenous relationships. Electron beam computed tomography allows acquisition and three-dimensional reconstruction of tomographic images of the beating heart with high spatial and temporal resolution. Contrast-enhanced, thin-section electron beam computed tomographic coronary arteriographic images of 34 patients (21 men and 13 women, age 60 ± 10 years) were analyzed. The visibility of the coronary veins and their spatial relationship to the coronary arteries were assessed qualitatively on two- and three-dimensional displays. The coronary sinus was visible in 91%, the great cardiac vein in 100%, the middle cardiac vein in 88%, at least one vein overlying the lateral surface of the left ventricle in 97%, the anterior interventricular vein in 97%, and the small cardiac vein in 68%. A left marginal and a left posterior vein were seen in 44%, one of the two in 38%, and neither in 3%. The course of the anterior interventricular vein was parallel to the left anterior coronary artery in 79% and a crossover between the two vessels at an obtuse angle occurred in 12%. Contrast-enhanced electron beam computed tomography imaging of the heart noninvasively provides information on the coronary venous system and arteriovenous relationships that may help guide new interventional procedures.
American Journal of Cardiology, 2003
In summary, these data indicate that in patients with severe coronary artery disease, rrMBF corre... more In summary, these data indicate that in patients with severe coronary artery disease, rrMBF correlates with EDV and LVEF, which may be explained by increased extravascular compressive forces that impair blood flow in intramyocardial vessels. Therefore, it appears necessary to consider EDV and LVEF in all studies that deal with absolute MBF to prevent the misinterpretation of results.
American Heart Journal, 2004
Coronary perforation is a serious but uncommon complication of percutaneous coronary intervention... more Coronary perforation is a serious but uncommon complication of percutaneous coronary intervention (PCI) and is associated with significant morbidity and mortality. We performed an analysis of the Mayo Clinic PCI database. Clinical records, procedural reports, and angiographic studies were reviewed. Multiple logistic regression analysis was performed to identify clinical, procedural, anatomic, and angiographic correlates of coronary perforation. A total of 16,298 PCI procedures were performed between January 1990 and December 2001. We identified 95 coronary perforations (0.58%; 95% CI, 0.47-0.71). The incidence of coronary perforation varied with time. Correlates of coronary perforation included the use of an atheroablative device and female sex. Twelve patients (12.6%) sustained an acute myocardial infarction, and cardiac tamponade developed in 11 patients (11.6%). Management strategies included reversal of heparin, pericardiocentesis, placement of a covered stent, and surgical repair. Seven patients died (7.4%). Coronary perforation during PCI is rare, but is associated with significant morbidity and mortality. The variable frequency of perforation may be explained by temporal variations in the use of atheroablative devices.
Journal of The American College of Cardiology, 2002
We sought to determine the effect of varying degrees of renal insufficiency on death and cardiac ... more We sought to determine the effect of varying degrees of renal insufficiency on death and cardiac events during and after a percutaneous coronary intervention (PCI). BACKGROUND Patients with end-stage renal disease have a high mortality from coronary artery disease. Little is known about the impact of mild and moderate renal insufficiency on clinical outcomes after PCI.
Journal of The American College of Cardiology, 1995
We sought to determine whether there is a gender bias in the selection of patients for coronary r... more We sought to determine whether there is a gender bias in the selection of patients for coronary revascularization once the severity of the underlying coronary artery disease has been established with angiography. It has been suggested that women with coronary artery disease are less likely to be referred for coronary angiography and coronary artery bypass surgery than men. Whether such a referral bias for revascularization procedures, including coronary angioplasty, is present once angiography has been performed is not clear. We retrospectively analyzed 22,795 patients with suspected coronary artery disease who underwent coronary angiography between 1981 and 1991 and compared the numbers of women and men who underwent either coronary artery bypass surgery or coronary angioplasty within 30 days of coronary angiography. Angiography revealed significant (one-vessel or more) disease in 15,455 patients (52% of women, 76% of men). Despite worse symptoms, women had less extensive coronary disease than men as judged by the number of vessels diseased. Women were also more likely to have other co-morbid diseases. An equal proportion of women (54%) and men underwent revascularization procedures. After adjustment for baseline differences and age, differences in the two individual revascularization strategies were very small: More women tended to have coronary angioplasty ([absolute difference +/- 1 SD] + 3.3 +/- 0.7%, p < 0.0001), but fewer had coronary artery bypass surgery than men (-2.5 +/- 0.8%, p = 0.003). When the two revascularization strategies were considered together, there was no significant gender difference in overall adjusted use of revascularization (+ 0.8 +/- 0.9%, p = 0.41). Once diagnostic coronary angiography had been performed, no major differences in the overall utilization of revascularization procedures were noted for women compared with men.
The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving ... more The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving coronary stents.
Journal of The American College of Cardiology, 1992
The aims of this study were to document the frequency of coronary artery aneurysm formation in pa... more The aims of this study were to document the frequency of coronary artery aneurysm formation in patients undergoing directional coronary atherectomy and to determine the relation of such aneurysms to the depth of arterial resection. Deep arterial injury is relatively frequent with the use of directional coronary atherectomy, but the potential for subsequent coronary artery aneurysm formation is unknown. Results in a consecutive series of 64 successfully treated patients (a total of 69 lesions; mean angiographic follow-up at 5 months) treated with directional coronary atherectomy were retrospectively analyzed with use of quantitative angiographic and histologic data. Coronary aneurysms (ratio of dilated vessel segment to the adjacent reference segment > 1.2:1) occurred in seven patients (10%). The only significant clinical correlate of aneurysm formation was a relatively shorter duration of angina. There were no significant preprocedural angiographic predictors of aneurysms, although 6 (86%) of the 7 aneurysmal lesions arose from restenosis lesions compared with 30 (48%) of 62 lesions with no subsequent aneurysm development (p = 0.06). Histopathologic examination of 414 specimens from 68 treated lesions showed no significant difference in the occurrence of subintimal resection (media +/- adventitia) between those with and without subsequent aneurysm (29% vs. 22%). Media alone was found in 14% of specimens from lesions that later became aneurysmal versus 15% of those that did not; adventitial resection was found in 14% and 7% of specimens, respectively (p = 0.08), with relatively more adventitia per specimen from those with aneurysm (55% vs. 30% without aneurysm, p = 0.08). Aneurysms occur relatively frequently after directional coronary atherectomy. Although there was no statistically significant correlation with the depth of arterial resection, the evidence from this study suggests that the role of adventitial resection in the occurrence of late aneurysm development should be explored further.
Journal of The American College of Cardiology, 1990
Rats afrestenosis wereevnlueted in 70 pstionts (74 Ierionr) after sueef&", 4ireetional e0roasry a... more Rats afrestenosis wereevnlueted in 70 pstionts (74 Ierionr) after sueef&", 4ireetional e0roasry atberf&lmy. The extent of vPr*r tissue reseelion wiu correlated with r&e. imshratesforewmmry (n = 59) and vein bye grntl CD = 15) lesimls.
Journal of The American College of Cardiology, 1999
The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving ... more The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving coronary stents.
Investigative Radiology, 1990
The authors examined the utility of cine computerized tomography (CT) for noninvasive determinati... more The authors examined the utility of cine computerized tomography (CT) for noninvasive determination of whole kidney, cortical, and medullary volumes. The right kidneys of 14 anesthetized dogs were scanned after an intravenous bolus injection of iohexol, and their volumes determined after boundary identification. After the scans, the kidneys were excised at postmortem examination and their volumes determined by fluid displacement. The mean (+/- standard error of the mean [SEM]) postmortem and in vivo renal volumes were 66.1 +/- 2.2 cc and 78.2 +/- 2.4 cc, respectively (r = 0.86; P less than 0.001). The difference was consistent with the blood, filtrate, and urine contents of the in vivo kidney. The in vivo cortical and medullary volumes correlated poorly with their postmortem volumes because of difficulties in boundary definition. These results demonstrate the feasibility for fast and reliable in vivo whole kidney volume quantitation by cine CT.
Journal of The American College of Cardiology, 1998
A Schmermund, BJ Rensing, PF Sheedy, MR Bell, and JA Rumberger segmental analysis of coronary art... more A Schmermund, BJ Rensing, PF Sheedy, MR Bell, and JA Rumberger segmental analysis of coronary artery stenoses Intravenous electron-beam computed tomographic coronary angiography for This information is current as of December 29, 2011 http://content.onlinejacc.org on the World Wide Web at:
American Journal of Medicine, 2000
Elderly patients, especially those 80 years of age and older, have been excluded from most studie... more Elderly patients, especially those 80 years of age and older, have been excluded from most studies of thrombolysis or primary coronary angioplasty in patients with acute myocardial infarction. We compared the outcomes of elderly patients who underwent coronary angioplasty with the outcomes of younger patients and determined whether there were any temporal trends in survival. We reviewed the outcomes of 1,597 consecutive patients who underwent primary coronary angioplasty between 1979 and 1997, including 127 patients who were 80 years of age or older (mean [+/-SD] age, 83 +/- 3 years, 47% male). Their in-hospital and long-term outcomes were compared with those of 524 patients who were 70 to 79 years old, 527 patients who were 60 to 69 years old, and 419 patients who were 50 to 59 years old. The oldest group of patients was divided into two groups, based on whether they had intervention through the end of 1993 (n = 56) or between 1994 and 1997 (n = 71). The survival rate of the patients who had no complications and left the hospital was compared with expected survival based on age- and sex-adjusted data. Patients 80 years of age or older had more adverse baseline characteristics, including risk factors and comorbid conditions, than the younger patients. The clinical success rate of primary angioplasty in this group was lower than those in the other three groups (61% versus 74% in those aged 70 to 79 years, 73% in those aged 60 to 69 years, and 81% in those aged 50 to 59 years, P < 0.001). The in-hospital mortality rate among patients 80 years of age or older was significantly greater than among patients in the other three groups (21% in those aged 80 years or older, 13% in those aged 70 to 79 years, 9% in those aged 60 to 69 years, and 4% in those aged 50 to 59 years, P < 0.001 ). The clinical success rate of the angioplasty improved significantly in the more recent period (75% versus 45%, P = 0.0006) and in-hospital mortality declined (16% versus 29%, P = 0.07). During follow-up, mortality in the oldest age group in whom angioplasty was successful was significantly greater than in the three younger groups, but was similar to the expected survival in the general US population. The mortality associated with primary angioplasty for acute myocardial infarction in octogenarians remains high, although there has been significant improvement in the clinical success rate. The long-term prognosis following a successful angioplasty is not different from that in an age- and sex-adjusted U.S. white population.
Catheterization and Cardiovascular Diagnosis, 1997
We describe a method of validation of computerized quantitative coronary arteriography and report... more We describe a method of validation of computerized quantitative coronary arteriography and report the results of a new UNIX-based quantitative coronary arteriography software program developed for rapid on-line (digital) and off-line (digital or cinefilm) analysis. The UNIX operating system is widely available in computer systems using very fast processors and has excellent graphics capabilities. The system is potentially compatible with any cardiac digital x-ray system for on-line analysis and has been designed to incorporate an integrated database, have on-line and immediate recall capabilities, and provide digital access to all data. The accuracy (mean signed differences of the observed minus the true dimensions) and precision (pooled standard deviations of the measurements) of the program were determined x-ray vessel phantoms. Intra- and interobserver variabilities were assessed from in vivo studies during routine clinical coronary arteriography. Precision from the x-ray phantom studies (6-In. field of view) for digital images was 0.066 mm and for digitized cine images was 0.060 mm. Accuracy was 0.076 mm (overestimation) for digital images compared to 0.008 mm for digitized cine images. Diagnostic coronary catheters were also used for calibration; accuracy.varied according to size of catheter and whether or not they were filled with iodinated contrast. Intra- and interobserver variabilities were excellent and indicated that coronary lesion measurements were relatively user-independent. Thus, this easy to use and very fast UNIX based program appears to be robust with optimal accuracy and precision for clinical and research applications.
American Heart Journal, 2000
ment of intracoronary stents, other new devices, and recently developed adjunctive pharmacologic ... more ment of intracoronary stents, other new devices, and recently developed adjunctive pharmacologic therapies.
Journal of The American College of Cardiology, 2002
Our goals were to identify clinical and angiographic risk factors associated with major cardiovas... more Our goals were to identify clinical and angiographic risk factors associated with major cardiovascular complications of percutaneous coronary intervention (PCI) (in-hospital death, Q-wave myocardial infarction, urgent or emergent coronary artery bypass surgery and stroke) and to construct a simple score for risk stratification. Both clinical and angiographic features influence risk of PCIs. Percutaneous coronary interventions performed between January 1, 1996, and December 31, 1999, were analyzed. Logistic regression and bootstrap methods were used to create an integer risk score for estimating the risk of procedural complications using baseline, angiographic and procedural characteristics. The risk score was tested in a validation-set consisting of all procedures performed in the year 2000. Among 5,463 procedures, 5 clinical and 3 angiographic variables were significantly correlated with procedural complications: cardiogenic shock, left main coronary artery disease, severe renal disease, urgent or emergent procedure, congestive heart failure class III or higher, thrombus, multivessel disease and older age. In the validation-set, the model fitted the data adequately; the average receiver operating characteristic curve area was 0.782 (standard deviation, 0.018). Eight variables were combined into a convenient bedside risk scoring system that estimates the risk of complications after PCIs.
Journal of The American College of Cardiology, 1999
The aim of this study was to accurately assess the radiation exposure received by patients during... more The aim of this study was to accurately assess the radiation exposure received by patients during cardiac catheterization in a large sample representative of the current state of practice in cardiac angiography.
Journal of The American College of Cardiology, 1990
Percutaneous t emerged as an luminal coronary an coronary artery disease; its use in patients wit... more Percutaneous t emerged as an luminal coronary an coronary artery disease; its use in patients with multivessel disease has resulted in high initial success rates incidence of complications (1-9). The long-term coronary angioplasty in these patients with multivessel disease remains controversial (HI,1 I) and is now the subject of several randomized trials. In particular, the consequence of incomplete revasculariz has become an important issue. Previous studies of nts with multivessel disease in whom revascularization with either angioplasty (2,4,12,13) : David R. Holmes, Jr.. MD. Mayo Clinic. 200 First Street SW, Rochester. Minnesota 55905. or surgery (14-N) was incom ave generally, but not always (tg), shown poorer sy atic outcome and survival compared with findings in patients in whom complete revascularization was achieved. Complete revascu~arizatio~ with coronary angio may not be achieved in patients with multivessel dise a variety of reasons including the presence of an occlusion or lesions either unsuitable ilate. The iong-term outco ted by these and other related v ree of revascu~arizat~o~ acbiev ous Tra~s~uminai Coronary Angioplasty onstrated that differences in ~~~~-terrn completely and into pletely revascularize multivessel disease could be explained largely in baseline patient characteristics (19).
American Journal of Cardiology, 1999
In patients receiving coronary stents treated with aspirin and coumadin, the peak incidence of st... more In patients receiving coronary stents treated with aspirin and coumadin, the peak incidence of stent thrombosis occurs on the fifth and sixth days following the implantation procedure. Little is known about the timing of stent thrombosis in patients treated with aspirin and ticlopidine. We compared the timing of coronary stent thrombosis in patients treated with ticlopidine and aspirin with the timing in those receiving coumadin and aspirin. A retrospective databank analysis was performed and 39 patients were identified who experienced stent thrombosis after successful coronary stent implantation. Of these, 21 had been treated with ticlopidine and aspirin and 18 with coumadin and aspirin therapy. The median time from stent implantation to stent thrombosis in the ticlopidine and aspirin group was 12 hours (interquartile range 6 to 72 hours) compared with 4 days in the coumadin and aspirin group (interquartile range 21 to 68 hours) (p <0.0001). There was no significant difference between the timing of stent thrombosis in patients treated with abciximab in addition to ticlopidine and aspirin (median 17 hours, interquartile range 6 to 29) versus ticlopidine and aspirin patients who did not receive abciximab (median 11 hours, interquartile range 9 to 12, p = 0.57). Thus, in patients who receive coronary stents, stent thrombosis occurs much earlier after the procedure in patients treated with ticlopidine and aspirin than in patients treated with anticoagulation therapy.
International Journal of Cardiovascular Imaging, 2001
New therapeutic strategies in interventional cardiology and electrophysiology involve the coronar... more New therapeutic strategies in interventional cardiology and electrophysiology involve the coronary veins. This study examines the potential usefulness of electron beam computed tomography to obtain detailed noninvasive definition of the coronary venous anatomy and of arteriovenous relationships. Electron beam computed tomography allows acquisition and three-dimensional reconstruction of tomographic images of the beating heart with high spatial and temporal resolution. Contrast-enhanced, thin-section electron beam computed tomographic coronary arteriographic images of 34 patients (21 men and 13 women, age 60 ± 10 years) were analyzed. The visibility of the coronary veins and their spatial relationship to the coronary arteries were assessed qualitatively on two- and three-dimensional displays. The coronary sinus was visible in 91%, the great cardiac vein in 100%, the middle cardiac vein in 88%, at least one vein overlying the lateral surface of the left ventricle in 97%, the anterior interventricular vein in 97%, and the small cardiac vein in 68%. A left marginal and a left posterior vein were seen in 44%, one of the two in 38%, and neither in 3%. The course of the anterior interventricular vein was parallel to the left anterior coronary artery in 79% and a crossover between the two vessels at an obtuse angle occurred in 12%. Contrast-enhanced electron beam computed tomography imaging of the heart noninvasively provides information on the coronary venous system and arteriovenous relationships that may help guide new interventional procedures.
American Journal of Cardiology, 2003
In summary, these data indicate that in patients with severe coronary artery disease, rrMBF corre... more In summary, these data indicate that in patients with severe coronary artery disease, rrMBF correlates with EDV and LVEF, which may be explained by increased extravascular compressive forces that impair blood flow in intramyocardial vessels. Therefore, it appears necessary to consider EDV and LVEF in all studies that deal with absolute MBF to prevent the misinterpretation of results.
American Heart Journal, 2004
Coronary perforation is a serious but uncommon complication of percutaneous coronary intervention... more Coronary perforation is a serious but uncommon complication of percutaneous coronary intervention (PCI) and is associated with significant morbidity and mortality. We performed an analysis of the Mayo Clinic PCI database. Clinical records, procedural reports, and angiographic studies were reviewed. Multiple logistic regression analysis was performed to identify clinical, procedural, anatomic, and angiographic correlates of coronary perforation. A total of 16,298 PCI procedures were performed between January 1990 and December 2001. We identified 95 coronary perforations (0.58%; 95% CI, 0.47-0.71). The incidence of coronary perforation varied with time. Correlates of coronary perforation included the use of an atheroablative device and female sex. Twelve patients (12.6%) sustained an acute myocardial infarction, and cardiac tamponade developed in 11 patients (11.6%). Management strategies included reversal of heparin, pericardiocentesis, placement of a covered stent, and surgical repair. Seven patients died (7.4%). Coronary perforation during PCI is rare, but is associated with significant morbidity and mortality. The variable frequency of perforation may be explained by temporal variations in the use of atheroablative devices.
Journal of The American College of Cardiology, 2002
We sought to determine the effect of varying degrees of renal insufficiency on death and cardiac ... more We sought to determine the effect of varying degrees of renal insufficiency on death and cardiac events during and after a percutaneous coronary intervention (PCI). BACKGROUND Patients with end-stage renal disease have a high mortality from coronary artery disease. Little is known about the impact of mild and moderate renal insufficiency on clinical outcomes after PCI.
Journal of The American College of Cardiology, 1995
We sought to determine whether there is a gender bias in the selection of patients for coronary r... more We sought to determine whether there is a gender bias in the selection of patients for coronary revascularization once the severity of the underlying coronary artery disease has been established with angiography. It has been suggested that women with coronary artery disease are less likely to be referred for coronary angiography and coronary artery bypass surgery than men. Whether such a referral bias for revascularization procedures, including coronary angioplasty, is present once angiography has been performed is not clear. We retrospectively analyzed 22,795 patients with suspected coronary artery disease who underwent coronary angiography between 1981 and 1991 and compared the numbers of women and men who underwent either coronary artery bypass surgery or coronary angioplasty within 30 days of coronary angiography. Angiography revealed significant (one-vessel or more) disease in 15,455 patients (52% of women, 76% of men). Despite worse symptoms, women had less extensive coronary disease than men as judged by the number of vessels diseased. Women were also more likely to have other co-morbid diseases. An equal proportion of women (54%) and men underwent revascularization procedures. After adjustment for baseline differences and age, differences in the two individual revascularization strategies were very small: More women tended to have coronary angioplasty ([absolute difference +/- 1 SD] + 3.3 +/- 0.7%, p < 0.0001), but fewer had coronary artery bypass surgery than men (-2.5 +/- 0.8%, p = 0.003). When the two revascularization strategies were considered together, there was no significant gender difference in overall adjusted use of revascularization (+ 0.8 +/- 0.9%, p = 0.41). Once diagnostic coronary angiography had been performed, no major differences in the overall utilization of revascularization procedures were noted for women compared with men.
The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving ... more The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving coronary stents.
Journal of The American College of Cardiology, 1992
The aims of this study were to document the frequency of coronary artery aneurysm formation in pa... more The aims of this study were to document the frequency of coronary artery aneurysm formation in patients undergoing directional coronary atherectomy and to determine the relation of such aneurysms to the depth of arterial resection. Deep arterial injury is relatively frequent with the use of directional coronary atherectomy, but the potential for subsequent coronary artery aneurysm formation is unknown. Results in a consecutive series of 64 successfully treated patients (a total of 69 lesions; mean angiographic follow-up at 5 months) treated with directional coronary atherectomy were retrospectively analyzed with use of quantitative angiographic and histologic data. Coronary aneurysms (ratio of dilated vessel segment to the adjacent reference segment > 1.2:1) occurred in seven patients (10%). The only significant clinical correlate of aneurysm formation was a relatively shorter duration of angina. There were no significant preprocedural angiographic predictors of aneurysms, although 6 (86%) of the 7 aneurysmal lesions arose from restenosis lesions compared with 30 (48%) of 62 lesions with no subsequent aneurysm development (p = 0.06). Histopathologic examination of 414 specimens from 68 treated lesions showed no significant difference in the occurrence of subintimal resection (media +/- adventitia) between those with and without subsequent aneurysm (29% vs. 22%). Media alone was found in 14% of specimens from lesions that later became aneurysmal versus 15% of those that did not; adventitial resection was found in 14% and 7% of specimens, respectively (p = 0.08), with relatively more adventitia per specimen from those with aneurysm (55% vs. 30% without aneurysm, p = 0.08). Aneurysms occur relatively frequently after directional coronary atherectomy. Although there was no statistically significant correlation with the depth of arterial resection, the evidence from this study suggests that the role of adventitial resection in the occurrence of late aneurysm development should be explored further.
Journal of The American College of Cardiology, 1990
Rats afrestenosis wereevnlueted in 70 pstionts (74 Ierionr) after sueef&", 4ireetional e0roasry a... more Rats afrestenosis wereevnlueted in 70 pstionts (74 Ierionr) after sueef&", 4ireetional e0roasry atberf&lmy. The extent of vPr*r tissue reseelion wiu correlated with r&e. imshratesforewmmry (n = 59) and vein bye grntl CD = 15) lesimls.
Journal of The American College of Cardiology, 1999
The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving ... more The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving coronary stents.