Walter Pae - Academia.edu (original) (raw)

Papers by Walter Pae

J Thorac Cardiovasc Surg, 2007

This study was undertaken to review the initial results and surgical safety data for the US Food ... more This study was undertaken to review the initial results and surgical safety data for the US Food and Drug Administration safety and feasibility trial of the Paracor HeartNet (Paracor Medical, Inc, Sunnyvale, Calif.) myocardial constraint device.Patients with New York Heart Association functional class II or III heart failure underwent device implantation (n = 21) through a left minithoracotomy.The average age was 53 years (31–72 years). There were 18 men and 3 women, and 17 patients had nonischemic etiology of heart failure. Mean heart failure duration was 8.3 years (1.4-18.8 years). Average ejection fraction was 22% (11%-33%), with an average left ventricular end-diastolic dimension of 74 mm (55-94 mm). Previous medical therapy included angiotensin-converting enzyme inhibitors, β-blockers, diuretics, digoxin, and aldosterone receptor blockers. At implantation, 17 patients had implantable electronic devices: 1 biventricular pacemaker, 11 biventricular pacemakers with cardioverter-defibrillators, and 5 implantable cardioverter-defibrillators. Patient comorbidities included hypertension in 10 cases, diabetes mellitus in 8, myocardial infarction in 1, and ventricular tachycardia in 8. Mean operative time was 68 minutes (42–102 minutes), and implantation time averaged 15 minutes (5–51 minutes). The average time to ambulation was 1.6 days (1–4 days). The intensive care unit stay averaged 3.3 days (1–16 days), and hospital stay averaged 6.3 days (4–16 days). Atrial fibrillation occurred in 2 patients, and there were 2 in-hospital deaths.The Paracor device can be implanted in patients with heart failure and reduced left ventricular function with a high degree of success. Significant surgical complications were infrequent. The initial US experience supports the conduct of a randomized, controlled, pivotal trial.

The Journal of Thoracic and Cardiovascular Surgery, Jan 31, 2008

An elastic ventricular restraint device has been developed for patients with heart failure who re... more An elastic ventricular restraint device has been developed for patients with heart failure who remain symptomatic despite treatment with standard therapies. The safety and efficacy of this device are under clinical investigation. Six-month data for the first 51 patients treated worldwide are reported. We hypothesize that the Paracor HeartNet device (Paracor Medical, Sunnyvale, Calif), placed through a minithoracotomy in patients with severe dilated cardiomyopathy, improves clinical and functional status. Fifty-one patients with an ejection fraction of 35% or less, with a New York Heart Association class II or III, and receiving optimal medical therapy for at least 3 months, were selected at 15 sites (3 in Europe, 12 in the United States) to undergo implantation of the HeartNet device through a minithoracotomy. Patients were evaluated at baseline and at 6-month follow-up by echocardiography, the 6-minute walk test, cardiopulmonary exercise testing (partial oxygen pressure in mixed venous blood), New York Heart Association class, and (in the United States) the Minnesota Living with Heart Failure questionnaire. The average age was 52 years (30-73 years), with a preponderance of men and nonischemic cause of heart failure. Implantation was accomplished in 50 of 51 patients (98%). Adverse events included 2 in-hospital deaths secondary to pulmonary complications (4%), additional pulmonary complications in 7 patients (14%), arrhythmia in 14 patients (27%), epicardial laceration in 2 patients (4%), and empyema in 1 patient (2%). Six-month data demonstrated significant improvement in the 6-minute walk test (+65.7, P = .002) and Minnesota Living with Heart Failure scores (-15.7, P = .002) and improvement in echocardiographic findings. The Paracor HeartNet device can be reliably implanted in patients with heart failure and marked reduction of left ventricular function. These data suggest a functional and clinical benefit, with a trend toward reverse remodeling, and support the conduct of a randomized controlled pivotal trial.

Journal of Applied Physiology, Feb 1, 2007

In animal studies, sympathetically mediated coronary vasoconstriction has been demonstrated durin... more In animal studies, sympathetically mediated coronary vasoconstriction has been demonstrated during exercise. Human studies examining coronary artery dynamics during exercise are technically difficult to perform. Recently, noninvasive transthoracic Duplex ultrasound studies demonstrated that: 1) patients with left internal mammary artery (LIMA) grafts to the left anterior descending artery can be imaged; and 2) the LIMA blood flow patterns are similar to those seen in normal coronary arteries. Accordingly, subjects with LIMA to the left anterior descending artery were studied during handgrip protocols as blood flow velocity in the LIMA was determined. Beat-by-beat analysis of changes in diastolic coronary blood flow velocity (CBV) was performed in six male clinically stable volunteers (60 ± 2 yrs) during two handgrip protocols. Arterial blood pressure (BP) and heart rate (HR) were also measured and an index of coronary vascular resistance (CVR) was calculated as diastolic BP/ CBV). Fatiguing handgrip performed at (40% of maximal voluntary contraction; MVC) followed by circulatory arrest did not evoke an increase in CVR (P = NS). In protocol 2, short bouts of handgrip (15 s) led to increases in CVR (18 ± 3% at 50% MVC and 20 ± 8% at 70% MVC). BP was also increased during handgrip. Our results reveal that in conscious humans, coronary vasoconstriction occurs within 15 s of onset of static handgrip at intensities at or greater than 50% MVC. These responses are likely to be due to sympathetic vasoconstriction of the coronary circulation.

ASAIO transactions / American Society for Artificial Internal Organs

ABSTRACT

The Annals of Thoracic Surgery

1. Ann Thorac Surg. 1993 Jan;55(1):206-12. Circulatory support 1991. The Second International Con... more 1. Ann Thorac Surg. 1993 Jan;55(1):206-12. Circulatory support 1991. The Second International Conference on Circulatory Support Devices for Severe Heart Failure. Patient selection. Pennington DG, Farrar DJ, Loisance D, Pae WE Jr, Emery RW. ...

JACC. Heart failure, 2015

ASAIO journal (American Society for Artificial Internal Organs : 1992)

The optimal timing of left ventricular assist device (LVAD) implantation in the management of adv... more The optimal timing of left ventricular assist device (LVAD) implantation in the management of advanced heart failure remains controversial. We hypothesize that in patients with cardiogenic shock, the severity of end-organ dysfunction as determined by the sequential organ failure assessment (SOFA) score is a determinant of outcomes after LVAD implantation. We determined the preoperative SOFA score and short- and long-term outcomes of 97 consecutive patients who received HeartMate II or HeartWare LVAD at our institution since January 2007. Kaplan-Meier analysis was used to compare long-term survival across SOFA score subgroups. The overall 30 day mortality was 10.1%, with no significant difference among SOFA score subgroups. Patients with scores ≥9 had significantly longer hospital stay (26 ± 6 vs. 18 ± 10 days, p = 0.03). One-year survival for SOFA scores 0-2, 3-5, 6-8, and ≥9 was 94%, 75%, 64%, and 29%, respectively. SOFA score was significantly lower in survivors at 6, 9, 12, 24, a...

ASAIO journal (American Society for Artificial Internal Organs : 1992)

Preexisting organ dysfunctions are known factors of death after placement of implantable mechanic... more Preexisting organ dysfunctions are known factors of death after placement of implantable mechanical circulatory support (MCS). Extracorporeal membrane oxygenation (ECMO) may able to stabilize organ function in patients with cardiogenic shock before MCS implantation. Between 2008 and 2012, 17 patients with cardiogenic shock were supported with ECMO before implantable MCS placement. Patient's end-organ functions were assessed by metabolic, cardiac, hepatic, renal, and respiratory parameters. Survival data after MCS implantations were analyzed for overall survival to discharge, complications, and breakpoint in days on ECMO to survival. Before MCS implantation, lactate, hepatic, and renal functions were improved and pulmonary edema was resolved. The interval between ECMO initiation and MCS placement was 12.1 ± 7.9 days. Overall survival rate to discharge after left ventricular assist device/total artificial heart placement was 76%. The survival of patients transitioned from ECMO to ...

The Journal of thoracic and cardiovascular surgery, 1993

An implantable, electrically powered pump that will provide tether-free circulatory support is be... more An implantable, electrically powered pump that will provide tether-free circulatory support is being developed. The blood pump consists of a seamless polyurethane sac within a polysulfone case. Björk-Shiley Monostrut valves provide unidirectional flow. The blood sac is compressed by a pusher plate with a stroke of 1.9 cm and actuated by a brushless direct-current electric motor and motion translator. The current unit is completely sealed, and inductive coupling techniques provide the electrical energy. The system has an implantable electronic control system as well as a battery that provides 30 minutes of operation when the external coil is disconnected. During normal operation, however, the pump is powered by a portable battery pack or by house current. The unit can pump 8.5 L/min at physiologic pressures. Twenty-six animals have had circulatory support for a period of more than 1 week. The average period of pumping was 62 days; the longest was nearly 8 months. Experiments were ter...

ASAIO transactions / American Society for Artificial Internal Organs

The authors developed, built, and tested in vivo a completely implanted total artificial heart (T... more The authors developed, built, and tested in vivo a completely implanted total artificial heart (TAH) system. The system used a reduced size version of a roller screw energy converter and mating sac blood pumps. The motor drive, pumps, and a compliance chamber were implanted intrathoracically. A canister containing controlling electronics and an emergency battery was implanted in the abdomen. The secondary coil of an inductive energy transmission and telemetry system was placed over the ribs. The system was implanted in three calves, that survived 0.5-13 days with the system. The system maintained safe left atrial pressures and adequate cardiac outputs during each animal's entire course.

Proceedings of the IEEE 28th Annual Northeast Bioengineering Conference (IEEE Cat. No.02CH37342), 2002

Left ventricular assist devices (LVADs) were implanted in calves for 30 days. The surface topogra... more Left ventricular assist devices (LVADs) were implanted in calves for 30 days. The surface topography of poly(urethane urea) blood sacs retrieved from the LVADs varied with blood pump flow rates and regions with different flow dynamics in the sac. Structures similar to those observed in a fibrin clot were observed in the inlets and outlets. The topography of the region between was distinctively different from that of the inlet and outlet

JACC: Heart Failure, 2014

The study sought to assess feasibility, safety, and potential efficacy of a novel implantable ext... more The study sought to assess feasibility, safety, and potential efficacy of a novel implantable extra-aortic counterpulsation system (C-Pulse) in functional class III and ambulatory functional class IV heart failure (HF) patients. 30% to 40% of HF patients suffer from poor functional status and quality of life (QoL) but are not in need of end-stage treatments. We undertook a multicenter single-arm study to assess the C-Pulse System in such patients. New York Heart Association (NYHA) functional class III or ambulatory functional class IV HF patients were eligible. Safety was assessed continuously through 12 months. Efficacy measurements included changes from baseline to 6 and 12 months in NYHA functional class, Minnesota Living with Heart Failure (MLWHF) and Kansas City Cardiomyopathy Questionnaire (KCCQ) scores, 6-min walk distance (6MWD), and exercise peak oxygen consumption (pVO2; 6 months only). Twelve men and 8 women (56.7 ± 7 years, 34 to 71 years of age) with ischemic (n = 7) or nonischemic (n = 13) cardiomyopathy were implanted. There was no 30-day mortality and no neurological events or myocardial infarctions through 12 months. At 6 months, there were 3 deaths (1 device-related). One-year survival was 85%. At 6 months, C-Pulse produced improvements in NYHA functional class (3.1 ± 0.3 to 1.9 ± 0.7, p = 0.0005), MLWHF (63.6 ± 19.9 to 40.2 ± 23.2, p = 0.0005), and KCCQ scores (43.6 ± 21.1 to 65.6 ± 21.5, p = 0.0002), but not 6MWD (275.5 ± 64.0 to 296.4 ± 104.9, p = NS) or pVO2 (14.5 ± 3.6 to 13.1 ± 4.4, p = NS). Improvements continued at 12 months, with 6MWD change becoming statistically significant (336.5 ± 91.8, p = 0.0425). Use of C-Pulse in this population is feasible, appears safe, and improves functional status and QoL. A prospective, multicenter, randomized controlled trial is underway. (C-Pulse IDE Feasability Study-A Heart Assist System; NCT00815880).

The Annals of thoracic surgery, 2014

We report a case of Takotsubo's syndrome in a 37-year-old woman after mitral valve repair for... more We report a case of Takotsubo's syndrome in a 37-year-old woman after mitral valve repair for severe mitral regurgitation triggered by a severe protamine reaction that was likely associated with immune-mediated coronary hypersensitivity (Kounis' syndrome) and made worse by resuscitation with high doses of catecholamines. The patient recovered fully after a 4-day course of extracorporeal membrane oxygenation therapy (ECMO).

Lead perforation is a rare complication of pacemakers and implantable cardioverter-defibrillators... more Lead perforation is a rare complication of pacemakers and implantable cardioverter-defibrillators (ICDs). The incidence with pacemakers has been reported from 0.1% to 1% whereas with ICDs the range is from 0.6% to 5.2%. We report the case of a subacute ventricular perforation in a 93-year-old woman. The patient had a VVI Medtronic (Mounds View, MN) single active-fixation lead pacemaker implanted at an outside hospital for symptomatic bradycardia. Twenty-eight days later she presented to the same hospital with complaints of chest pain and shortness of breath. An electrocardiogram showed failure to capture, which was confirmed on pacemaker interrogation. The chest radiograph showed the pacer lead extending beyond the cardiac margins and a small left pleural effusion. She was then transferred to our hospital where computed tomography (CT) of the thorax confirmed lead extension through the right ventricular wall apex, pericardium, into the left pleural space, anterior to the lingua with...

support devices for chronic heart failure Bethesda conference: conference for the design of clini... more support devices for chronic heart failure Bethesda conference: conference for the design of clinical trials to study circulatory http://ats.ctsnetjournals.org/cgi/content/full/66/4/1452 on the World Wide Web at: The online version of this article, along with updated information and services, is located Print ISSN: 0003-4975; eISSN: 1552-6259. Southern Thoracic Surgical Association.

The Heart Surgery Forum, 2014

Heart failure is associated with prolonged stress and inflammation characterized by elevated leve... more Heart failure is associated with prolonged stress and inflammation characterized by elevated levels of cortisol and circulating catecholamines. Persistent sympathetic stimulation secondary to the stress of heart failure causes an induced insulin resistance, which creates a need for higher doses of insulin to adequately manage hyperglycemia in this patient population. We hypothesized that cortisol and catecholamine levels would be elevated in end-stage heart failure patients, however, would be reduced after the implantation of a left ventricular assist device (LVAD). Insulin requirements would therefore be reduced post LVAD implant and control of diabetes improved as compared with pre-implant. Pre- and postoperative cortisol, catecholamine, glycated hemoglobin, and blood glucose levels were evaluated retrospectively in 99 LVAD patients at a single center from January 2007 through November 2011. Serum was collected before LVAD implantation and monthly after implantation for 12 months consecutively. Results were evaluated and compared to insulin requirements, if any, before and after implant. Plasma levels were measured by ELISA. There were a total of 99 patients (81 men and 18 women). Two patients were implanted twice due to pump dysfunction. Mean age was 59 years, ± 10, with a median of 63 years. Of those patients, 64 had ischemic cardiomyopathy and 35 had dilated cardiomyopathy. The total patient years of LVAD support were 92.5 years. All patients received a continuous flow left ventricular assist device. Type II diabetes mellitus was diagnosed in 28 patients. Of those patients, 24 required daily insulin with an average dose of 45 units/day. Average preoperative glycated hemoglobin (HbA1c) levels were 6.8% with fasting blood glucose measurements of 136 mg/dL. Mean cortisol levels were measured at 24.3 μg/dL before LVAD implantation, with mean plasma catecholamine levels of 1824 μg/mL. Post operatively, average HbA1c levels were 5.38% with fasting blood glucose measurements of 122 mg/dL. Mean cortisol levels were measured at 10.9 μg/dL with average plasma catecholamine levels were 815 μg/mL. There was a significant decrease in both cortisol levels post LVAD implant (P = 0.012) as well as catecholamine levels (P = 0.044). The average insulin requirements post LVAD implant were significantly reduced to 13 units/day (P = 0.001). Six patients no longer required any insulin after implant. Implantation of nonpulsatile LVADs has become a viable option for the treatment of end-stage heart failure, helping to improve patient quality of life by decreasing clinical symptoms associated with poor end-organ perfusion. Frequently, diabetes is a comorbid condition that exists among heart failure patients and with the reduction of the systemic inflammatory and stress response produced by the support of a nonpulsatile LVAD, many patients may benefit from a reduction in their blood glucose levels, as well as insulin requirements.

New England Journal of Medicine, 1988

Heterotopic prosthetic ventricles were used to support the circulation in 29 candidates for heart... more Heterotopic prosthetic ventricles were used to support the circulation in 29 candidates for heart transplantation who were expected to die before procurement of a donor heart. Twenty-one of these patients (average age, 36 years) underwent successful transplantation after 8 hours to 31 days of circulatory support. The other eight patients died because their condition could not be stabilized for transplantation, despite restoration of blood flow. Fourteen patients received biventricular support; 15 received only left ventricular support, with pharmacologic assistance of right heart function. Before transplantation, blood flow from the left prosthetic ventricle averaged 2.8 +/- 0.4 liters per minute per square meter of body-surface area, and from the right prosthesis 2.4 +/- 0.4 liters, as compared with an average flow of 1.6 +/- 0.5 liters per minute per square meter before implantation. Of the 21 patients who received heart transplants, 20 were discharged from the hospital after a median of 31 days. Nineteen patients were alive at 7 to 39 months, and 11 of the first 12 were alive at one year. We conclude that heterotopic placement of prosthetic ventricles as a bridge to transplantation provides an effective method of temporarily supporting cardiac function in critically ill patients without removing the natural heart. The early survival rate after transplantation is similar to that with elective cardiac transplantation.

J Thorac Cardiovasc Surg, 2007

This study was undertaken to review the initial results and surgical safety data for the US Food ... more This study was undertaken to review the initial results and surgical safety data for the US Food and Drug Administration safety and feasibility trial of the Paracor HeartNet (Paracor Medical, Inc, Sunnyvale, Calif.) myocardial constraint device.Patients with New York Heart Association functional class II or III heart failure underwent device implantation (n = 21) through a left minithoracotomy.The average age was 53 years (31–72 years). There were 18 men and 3 women, and 17 patients had nonischemic etiology of heart failure. Mean heart failure duration was 8.3 years (1.4-18.8 years). Average ejection fraction was 22% (11%-33%), with an average left ventricular end-diastolic dimension of 74 mm (55-94 mm). Previous medical therapy included angiotensin-converting enzyme inhibitors, β-blockers, diuretics, digoxin, and aldosterone receptor blockers. At implantation, 17 patients had implantable electronic devices: 1 biventricular pacemaker, 11 biventricular pacemakers with cardioverter-defibrillators, and 5 implantable cardioverter-defibrillators. Patient comorbidities included hypertension in 10 cases, diabetes mellitus in 8, myocardial infarction in 1, and ventricular tachycardia in 8. Mean operative time was 68 minutes (42–102 minutes), and implantation time averaged 15 minutes (5–51 minutes). The average time to ambulation was 1.6 days (1–4 days). The intensive care unit stay averaged 3.3 days (1–16 days), and hospital stay averaged 6.3 days (4–16 days). Atrial fibrillation occurred in 2 patients, and there were 2 in-hospital deaths.The Paracor device can be implanted in patients with heart failure and reduced left ventricular function with a high degree of success. Significant surgical complications were infrequent. The initial US experience supports the conduct of a randomized, controlled, pivotal trial.

The Journal of Thoracic and Cardiovascular Surgery, Jan 31, 2008

An elastic ventricular restraint device has been developed for patients with heart failure who re... more An elastic ventricular restraint device has been developed for patients with heart failure who remain symptomatic despite treatment with standard therapies. The safety and efficacy of this device are under clinical investigation. Six-month data for the first 51 patients treated worldwide are reported. We hypothesize that the Paracor HeartNet device (Paracor Medical, Sunnyvale, Calif), placed through a minithoracotomy in patients with severe dilated cardiomyopathy, improves clinical and functional status. Fifty-one patients with an ejection fraction of 35% or less, with a New York Heart Association class II or III, and receiving optimal medical therapy for at least 3 months, were selected at 15 sites (3 in Europe, 12 in the United States) to undergo implantation of the HeartNet device through a minithoracotomy. Patients were evaluated at baseline and at 6-month follow-up by echocardiography, the 6-minute walk test, cardiopulmonary exercise testing (partial oxygen pressure in mixed venous blood), New York Heart Association class, and (in the United States) the Minnesota Living with Heart Failure questionnaire. The average age was 52 years (30-73 years), with a preponderance of men and nonischemic cause of heart failure. Implantation was accomplished in 50 of 51 patients (98%). Adverse events included 2 in-hospital deaths secondary to pulmonary complications (4%), additional pulmonary complications in 7 patients (14%), arrhythmia in 14 patients (27%), epicardial laceration in 2 patients (4%), and empyema in 1 patient (2%). Six-month data demonstrated significant improvement in the 6-minute walk test (+65.7, P = .002) and Minnesota Living with Heart Failure scores (-15.7, P = .002) and improvement in echocardiographic findings. The Paracor HeartNet device can be reliably implanted in patients with heart failure and marked reduction of left ventricular function. These data suggest a functional and clinical benefit, with a trend toward reverse remodeling, and support the conduct of a randomized controlled pivotal trial.

Journal of Applied Physiology, Feb 1, 2007

In animal studies, sympathetically mediated coronary vasoconstriction has been demonstrated durin... more In animal studies, sympathetically mediated coronary vasoconstriction has been demonstrated during exercise. Human studies examining coronary artery dynamics during exercise are technically difficult to perform. Recently, noninvasive transthoracic Duplex ultrasound studies demonstrated that: 1) patients with left internal mammary artery (LIMA) grafts to the left anterior descending artery can be imaged; and 2) the LIMA blood flow patterns are similar to those seen in normal coronary arteries. Accordingly, subjects with LIMA to the left anterior descending artery were studied during handgrip protocols as blood flow velocity in the LIMA was determined. Beat-by-beat analysis of changes in diastolic coronary blood flow velocity (CBV) was performed in six male clinically stable volunteers (60 ± 2 yrs) during two handgrip protocols. Arterial blood pressure (BP) and heart rate (HR) were also measured and an index of coronary vascular resistance (CVR) was calculated as diastolic BP/ CBV). Fatiguing handgrip performed at (40% of maximal voluntary contraction; MVC) followed by circulatory arrest did not evoke an increase in CVR (P = NS). In protocol 2, short bouts of handgrip (15 s) led to increases in CVR (18 ± 3% at 50% MVC and 20 ± 8% at 70% MVC). BP was also increased during handgrip. Our results reveal that in conscious humans, coronary vasoconstriction occurs within 15 s of onset of static handgrip at intensities at or greater than 50% MVC. These responses are likely to be due to sympathetic vasoconstriction of the coronary circulation.

ASAIO transactions / American Society for Artificial Internal Organs

ABSTRACT

The Annals of Thoracic Surgery

1. Ann Thorac Surg. 1993 Jan;55(1):206-12. Circulatory support 1991. The Second International Con... more 1. Ann Thorac Surg. 1993 Jan;55(1):206-12. Circulatory support 1991. The Second International Conference on Circulatory Support Devices for Severe Heart Failure. Patient selection. Pennington DG, Farrar DJ, Loisance D, Pae WE Jr, Emery RW. ...

JACC. Heart failure, 2015

ASAIO journal (American Society for Artificial Internal Organs : 1992)

The optimal timing of left ventricular assist device (LVAD) implantation in the management of adv... more The optimal timing of left ventricular assist device (LVAD) implantation in the management of advanced heart failure remains controversial. We hypothesize that in patients with cardiogenic shock, the severity of end-organ dysfunction as determined by the sequential organ failure assessment (SOFA) score is a determinant of outcomes after LVAD implantation. We determined the preoperative SOFA score and short- and long-term outcomes of 97 consecutive patients who received HeartMate II or HeartWare LVAD at our institution since January 2007. Kaplan-Meier analysis was used to compare long-term survival across SOFA score subgroups. The overall 30 day mortality was 10.1%, with no significant difference among SOFA score subgroups. Patients with scores ≥9 had significantly longer hospital stay (26 ± 6 vs. 18 ± 10 days, p = 0.03). One-year survival for SOFA scores 0-2, 3-5, 6-8, and ≥9 was 94%, 75%, 64%, and 29%, respectively. SOFA score was significantly lower in survivors at 6, 9, 12, 24, a...

ASAIO journal (American Society for Artificial Internal Organs : 1992)

Preexisting organ dysfunctions are known factors of death after placement of implantable mechanic... more Preexisting organ dysfunctions are known factors of death after placement of implantable mechanical circulatory support (MCS). Extracorporeal membrane oxygenation (ECMO) may able to stabilize organ function in patients with cardiogenic shock before MCS implantation. Between 2008 and 2012, 17 patients with cardiogenic shock were supported with ECMO before implantable MCS placement. Patient's end-organ functions were assessed by metabolic, cardiac, hepatic, renal, and respiratory parameters. Survival data after MCS implantations were analyzed for overall survival to discharge, complications, and breakpoint in days on ECMO to survival. Before MCS implantation, lactate, hepatic, and renal functions were improved and pulmonary edema was resolved. The interval between ECMO initiation and MCS placement was 12.1 ± 7.9 days. Overall survival rate to discharge after left ventricular assist device/total artificial heart placement was 76%. The survival of patients transitioned from ECMO to ...

The Journal of thoracic and cardiovascular surgery, 1993

An implantable, electrically powered pump that will provide tether-free circulatory support is be... more An implantable, electrically powered pump that will provide tether-free circulatory support is being developed. The blood pump consists of a seamless polyurethane sac within a polysulfone case. Björk-Shiley Monostrut valves provide unidirectional flow. The blood sac is compressed by a pusher plate with a stroke of 1.9 cm and actuated by a brushless direct-current electric motor and motion translator. The current unit is completely sealed, and inductive coupling techniques provide the electrical energy. The system has an implantable electronic control system as well as a battery that provides 30 minutes of operation when the external coil is disconnected. During normal operation, however, the pump is powered by a portable battery pack or by house current. The unit can pump 8.5 L/min at physiologic pressures. Twenty-six animals have had circulatory support for a period of more than 1 week. The average period of pumping was 62 days; the longest was nearly 8 months. Experiments were ter...

ASAIO transactions / American Society for Artificial Internal Organs

The authors developed, built, and tested in vivo a completely implanted total artificial heart (T... more The authors developed, built, and tested in vivo a completely implanted total artificial heart (TAH) system. The system used a reduced size version of a roller screw energy converter and mating sac blood pumps. The motor drive, pumps, and a compliance chamber were implanted intrathoracically. A canister containing controlling electronics and an emergency battery was implanted in the abdomen. The secondary coil of an inductive energy transmission and telemetry system was placed over the ribs. The system was implanted in three calves, that survived 0.5-13 days with the system. The system maintained safe left atrial pressures and adequate cardiac outputs during each animal's entire course.

Proceedings of the IEEE 28th Annual Northeast Bioengineering Conference (IEEE Cat. No.02CH37342), 2002

Left ventricular assist devices (LVADs) were implanted in calves for 30 days. The surface topogra... more Left ventricular assist devices (LVADs) were implanted in calves for 30 days. The surface topography of poly(urethane urea) blood sacs retrieved from the LVADs varied with blood pump flow rates and regions with different flow dynamics in the sac. Structures similar to those observed in a fibrin clot were observed in the inlets and outlets. The topography of the region between was distinctively different from that of the inlet and outlet

JACC: Heart Failure, 2014

The study sought to assess feasibility, safety, and potential efficacy of a novel implantable ext... more The study sought to assess feasibility, safety, and potential efficacy of a novel implantable extra-aortic counterpulsation system (C-Pulse) in functional class III and ambulatory functional class IV heart failure (HF) patients. 30% to 40% of HF patients suffer from poor functional status and quality of life (QoL) but are not in need of end-stage treatments. We undertook a multicenter single-arm study to assess the C-Pulse System in such patients. New York Heart Association (NYHA) functional class III or ambulatory functional class IV HF patients were eligible. Safety was assessed continuously through 12 months. Efficacy measurements included changes from baseline to 6 and 12 months in NYHA functional class, Minnesota Living with Heart Failure (MLWHF) and Kansas City Cardiomyopathy Questionnaire (KCCQ) scores, 6-min walk distance (6MWD), and exercise peak oxygen consumption (pVO2; 6 months only). Twelve men and 8 women (56.7 ± 7 years, 34 to 71 years of age) with ischemic (n = 7) or nonischemic (n = 13) cardiomyopathy were implanted. There was no 30-day mortality and no neurological events or myocardial infarctions through 12 months. At 6 months, there were 3 deaths (1 device-related). One-year survival was 85%. At 6 months, C-Pulse produced improvements in NYHA functional class (3.1 ± 0.3 to 1.9 ± 0.7, p = 0.0005), MLWHF (63.6 ± 19.9 to 40.2 ± 23.2, p = 0.0005), and KCCQ scores (43.6 ± 21.1 to 65.6 ± 21.5, p = 0.0002), but not 6MWD (275.5 ± 64.0 to 296.4 ± 104.9, p = NS) or pVO2 (14.5 ± 3.6 to 13.1 ± 4.4, p = NS). Improvements continued at 12 months, with 6MWD change becoming statistically significant (336.5 ± 91.8, p = 0.0425). Use of C-Pulse in this population is feasible, appears safe, and improves functional status and QoL. A prospective, multicenter, randomized controlled trial is underway. (C-Pulse IDE Feasability Study-A Heart Assist System; NCT00815880).

The Annals of thoracic surgery, 2014

We report a case of Takotsubo's syndrome in a 37-year-old woman after mitral valve repair for... more We report a case of Takotsubo's syndrome in a 37-year-old woman after mitral valve repair for severe mitral regurgitation triggered by a severe protamine reaction that was likely associated with immune-mediated coronary hypersensitivity (Kounis' syndrome) and made worse by resuscitation with high doses of catecholamines. The patient recovered fully after a 4-day course of extracorporeal membrane oxygenation therapy (ECMO).

Lead perforation is a rare complication of pacemakers and implantable cardioverter-defibrillators... more Lead perforation is a rare complication of pacemakers and implantable cardioverter-defibrillators (ICDs). The incidence with pacemakers has been reported from 0.1% to 1% whereas with ICDs the range is from 0.6% to 5.2%. We report the case of a subacute ventricular perforation in a 93-year-old woman. The patient had a VVI Medtronic (Mounds View, MN) single active-fixation lead pacemaker implanted at an outside hospital for symptomatic bradycardia. Twenty-eight days later she presented to the same hospital with complaints of chest pain and shortness of breath. An electrocardiogram showed failure to capture, which was confirmed on pacemaker interrogation. The chest radiograph showed the pacer lead extending beyond the cardiac margins and a small left pleural effusion. She was then transferred to our hospital where computed tomography (CT) of the thorax confirmed lead extension through the right ventricular wall apex, pericardium, into the left pleural space, anterior to the lingua with...

support devices for chronic heart failure Bethesda conference: conference for the design of clini... more support devices for chronic heart failure Bethesda conference: conference for the design of clinical trials to study circulatory http://ats.ctsnetjournals.org/cgi/content/full/66/4/1452 on the World Wide Web at: The online version of this article, along with updated information and services, is located Print ISSN: 0003-4975; eISSN: 1552-6259. Southern Thoracic Surgical Association.

The Heart Surgery Forum, 2014

Heart failure is associated with prolonged stress and inflammation characterized by elevated leve... more Heart failure is associated with prolonged stress and inflammation characterized by elevated levels of cortisol and circulating catecholamines. Persistent sympathetic stimulation secondary to the stress of heart failure causes an induced insulin resistance, which creates a need for higher doses of insulin to adequately manage hyperglycemia in this patient population. We hypothesized that cortisol and catecholamine levels would be elevated in end-stage heart failure patients, however, would be reduced after the implantation of a left ventricular assist device (LVAD). Insulin requirements would therefore be reduced post LVAD implant and control of diabetes improved as compared with pre-implant. Pre- and postoperative cortisol, catecholamine, glycated hemoglobin, and blood glucose levels were evaluated retrospectively in 99 LVAD patients at a single center from January 2007 through November 2011. Serum was collected before LVAD implantation and monthly after implantation for 12 months consecutively. Results were evaluated and compared to insulin requirements, if any, before and after implant. Plasma levels were measured by ELISA. There were a total of 99 patients (81 men and 18 women). Two patients were implanted twice due to pump dysfunction. Mean age was 59 years, ± 10, with a median of 63 years. Of those patients, 64 had ischemic cardiomyopathy and 35 had dilated cardiomyopathy. The total patient years of LVAD support were 92.5 years. All patients received a continuous flow left ventricular assist device. Type II diabetes mellitus was diagnosed in 28 patients. Of those patients, 24 required daily insulin with an average dose of 45 units/day. Average preoperative glycated hemoglobin (HbA1c) levels were 6.8% with fasting blood glucose measurements of 136 mg/dL. Mean cortisol levels were measured at 24.3 μg/dL before LVAD implantation, with mean plasma catecholamine levels of 1824 μg/mL. Post operatively, average HbA1c levels were 5.38% with fasting blood glucose measurements of 122 mg/dL. Mean cortisol levels were measured at 10.9 μg/dL with average plasma catecholamine levels were 815 μg/mL. There was a significant decrease in both cortisol levels post LVAD implant (P = 0.012) as well as catecholamine levels (P = 0.044). The average insulin requirements post LVAD implant were significantly reduced to 13 units/day (P = 0.001). Six patients no longer required any insulin after implant. Implantation of nonpulsatile LVADs has become a viable option for the treatment of end-stage heart failure, helping to improve patient quality of life by decreasing clinical symptoms associated with poor end-organ perfusion. Frequently, diabetes is a comorbid condition that exists among heart failure patients and with the reduction of the systemic inflammatory and stress response produced by the support of a nonpulsatile LVAD, many patients may benefit from a reduction in their blood glucose levels, as well as insulin requirements.

New England Journal of Medicine, 1988

Heterotopic prosthetic ventricles were used to support the circulation in 29 candidates for heart... more Heterotopic prosthetic ventricles were used to support the circulation in 29 candidates for heart transplantation who were expected to die before procurement of a donor heart. Twenty-one of these patients (average age, 36 years) underwent successful transplantation after 8 hours to 31 days of circulatory support. The other eight patients died because their condition could not be stabilized for transplantation, despite restoration of blood flow. Fourteen patients received biventricular support; 15 received only left ventricular support, with pharmacologic assistance of right heart function. Before transplantation, blood flow from the left prosthetic ventricle averaged 2.8 +/- 0.4 liters per minute per square meter of body-surface area, and from the right prosthesis 2.4 +/- 0.4 liters, as compared with an average flow of 1.6 +/- 0.5 liters per minute per square meter before implantation. Of the 21 patients who received heart transplants, 20 were discharged from the hospital after a median of 31 days. Nineteen patients were alive at 7 to 39 months, and 11 of the first 12 were alive at one year. We conclude that heterotopic placement of prosthetic ventricles as a bridge to transplantation provides an effective method of temporarily supporting cardiac function in critically ill patients without removing the natural heart. The early survival rate after transplantation is similar to that with elective cardiac transplantation.