Mario Valenza - Academia.edu (original) (raw)

Papers by Mario Valenza

Journal of The American College of Cardiology, 1988

Phosphorus-31 nuclear magnetic resonance spectroscopy can determine the status of high energy pho... more Phosphorus-31 nuclear magnetic resonance spectroscopy can determine the status of high energy phosphates in vivo. However, its application to human cardiac studies requires precise spatial localization without significant contamination from other tissues. Using image-selected in-vivo spectroscopy (ISIS), a technique that allows three-dimensional localization of the volume of interest, 12 subjects were studied to determine the feasibility and reproducibility of phosphorus-31 spectroscopy of the human heart. Nuclear magnetic resonance imaging was performed using a commercial 1.5 tesla system to define the volume of interest. Phosphorus-31 spectra were obtained from the septum and anteroapical region of the left ventricle in 10 studies. Relative peak heights and areas were determined for high energy phosphates. The mean phosphocreatine to adenosine triphosphate ratio was 1.33 +/- 0.19 by height analysis and 1.23 +/- 0.27 by area analysis. Duplicate measurements in four subjects showed a reproducibility of less than or equal to 10% in three of the subjects. All spectra showed significant signal contribution from the 2,3 diphosphoglycerate in chamber red cells without evidence of skeletal muscle contamination. These results demonstrate the feasibility of image-guided phosphorus-31 spectroscopy for human cardiac studies and indicate the potential of this technique to study metabolic disturbances in human myocardial disease.

International Journal of Cardiology, 1993

The study aimed at checking effects exerted by captopril (C) on human myocardial ACE system as we... more The study aimed at checking effects exerted by captopril (C) on human myocardial ACE system as well as the role played by tissue ACE inhibition in reducing reperfusion damage. A human experimental model was used during cardioplegia due to aorto-coronary-by-pass (CABG). Fifty-four patients with coronary artery disease affecting 3 vessels having suffered from acute myocardial infarction anterior (AMI-ant), homogeneous as far as ejection fraction (35-55%). number of grafts (3), clamping time, age and sex, were randomised in a double blind experiment, and were given captopril or placebo (P). A total of 4 mg/I Captopril was mixed into the cardioplegic solution with blood according to the method of Buckberg (Buckberg GD. J Thorac Cardiovasc Surg 1987; 93: 127-139). Eight samples (blood/perfusate) were obtained from each patients and norepinephrine (NE). epinephrine (E) were assayed using an HPLC technique. Angiotensin 1 was assayed by RIA. CK was also assayed (units/ml). Bloodiperfusate samples were taken during CABG: (I) pre-pump; (2) pump sample; (3) pump preclamping; (4) coronary sinus; (5) coronary sinus sample during reperfusion; (6) coronary sinus during warm reperfusion; (7) after clamping sample; after decanulation; Results: Captopril group (29 patients): angiotensin I: () 399; pg/ml (P < 0.01). CK, captopril group: (I) 79; (2) 95; (3) 100; (4) 94; (5) 104; (6) 94; (7) 108; (8) 108; vs. placebo: (I) 76; (2) 120; (3) 135; (4) 152 (5) 225; (6) 272; (7) 247; (8) 228; units/ml. (P < 0.01).

Journal of The American College of Cardiology, 1995

Conclusions: Late left sided stenoses are common in isolated neonatal COA and often develop by 1 ... more Conclusions: Late left sided stenoses are common in isolated neonatal COA and often develop by 1 yr of age. Echocardiography can identify patients at increased risk for these progressive lesions.

Annals of Thoracic Surgery, 1994

Thoracic and Cardiovascular Surgeon, 1997

The effective treatment of refractory allograft rejection with murine antihuman monoclonal antibo... more The effective treatment of refractory allograft rejection with murine antihuman monoclonal antibody muromonab-CD3 (OKT3) and of patients with renal dysfunction has led to its use as induction therapy. The optimal protocol for OKT3 prophylaxis remains to be established. We compared 59 patients consecutively transplanted with the total orthotopic technique between 1/92 and 5/94. The first 21 patients were treated with OKT3 for 14 days, the next 19 for 10 days, and the last 19 for 7 days. Patients operated with different surgical techniques or other induction treatment were excluded. We compared length of stay (total and ICU), time to first rejection, rejection incidence and infection incidence (cytomegalovirus separately), and survival. Preoperative characteristics were similar except for significantly younger age in the 10-day group (p = 0.04). Preoperative hemodynamic parameters were similar except for a significantly higher left-ventricular ejection fraction (21%) in the 7-day group. Length of stays in the ICU and hospital were similar for the three groups (p = NS). Freedom from cellular rejection was lower with the 7 days course (p = 0.02), but freedom from humoral rejection was slightly higher (p = 0.11). However, patients in the 7-day group required treatment for rejection less frequently than patients in the other two groups (95% untreated at 2 months vs. 43% in the 14-day and 53% in the 10-day group; p = 0.002). There were no differences in incidence of infections, including cytomegalovirus. Survival was similar between the groups. There was one death in the 14-day and 1 in the 10-day group, both due to rejection. In conclusion, OKT3 therapy can be reduced safely to 7 days with a higher overall incidence of rejection but no increased necessity to treat for rejection, and no difference in infection incidence.

Cardiovascular Surgery, 1995

Annals of Thoracic Surgery, 1994

We present our experience with an alternative technique for orthotopic heart transplantation. It ... more We present our experience with an alternative technique for orthotopic heart transplantation. It consists of total excision of the recipient's atria, with the donor's heart implantation performed using bicaval end-to-end anastomoses as well as pulmonary venous anastomoses. Forty consecutive patients receiving transplants in this fashion were compared with 64 patients who underwent orthotopic transplantation with the standard technique. The incidence of postoperative tricuspid regurgitation was reduced in patients receiving transplants with the new surgical approach (p = 0.003). In addition, the need for

Annals of Thoracic Surgery, 1994

An alternative technique for orthotopic heart transplantation is described. The principle consist... more An alternative technique for orthotopic heart transplantation is described. The principle consists of total excision of the recipient's right atrium with donor heart implantation performed using bicaval anastomoses; the left atrium is done in the standard fashion. This approach is technically simple and preserves the anatomic and physiologic function and integrity of the right atrium, especially the conduction system.

American Heart Journal, 1995

Orthotopic heart transplantation (OHT) with bicaval and pulmonary venous anastomoses avoids the l... more Orthotopic heart transplantation (OHT) with bicaval and pulmonary venous anastomoses avoids the large atrial anastomoses of the standard biatrial technique. To determine whether the bicaval technique improves atrial performance, we used Doppler echocardiography to study 13 patients with bicaval OHT, 15 with biatrial OHT, and 8 normal subjects. All were in sinus rhythm and free of rejection. Left atrial size, transmitral (M) and late diastolic (A) mitral flow velocity integrals were measured. Atrial transport (A/M, %) and atrial ejection force (kilodynes, calculated from peak A-wave velocity and mitral orifice area) were assessed. Left atrial dimensions in the bicaval (4.3 + 0.5 cm) and biatrial groups

Thoracic and Cardiovascular Surgeon, 1996

Objective: Pretransplant pulmonary vascular resistance ] 4 Wood-units predisposes to right ventri... more Objective: Pretransplant pulmonary vascular resistance ] 4 Wood-units predisposes to right ventricular failure after heart transplantation. Total orthotopic heart transplantation with bicaval and pulmonary venous anastomoses offers synchronous contractions of the atria and a normal ventricular filling pattern, but requires longer ischemic time than standard orthotopic heart transplantation. To test if total orthotopic heart transplantation improves resting hemodynamics in pts with high preoperative pulmonary vascular resistance, we analyzed 65 pts with standard and 65 with total orthotopic heart transplantation transplanted between 12/88 and 7/94. Of these, 18 with total and 15 with standard orthotopic heart transplantation had a preoperative pulmonary vascular resistance ]4 Wood-units. Methods: Right heart catheterization data were obtained at each endomyocardial biopsy. All data from biopsies at both 2 weeks and 1 year posttransplant that were free from humoral or greater than 1A cellular rejection (9 versus 13 pts) were included in a two way ANOVA. Pts with postop pacemakers, atrial fib or i-blocker therapy at the time of biopsy were excluded. Results: Ischemic time was different (172 9 44 versus 142928 min, P = 0.03). Demographics, NYHA class, pre-TX hemodynamics, donor age and inotropes were similar. Cardiac output and index were higher in the total orthotopic group at 2 weeks (6.591.7 versus 5.19 1.0 l/min; 3.4 9 0.9 versus 2.89 0.6 l/min per m 2 ) and 1 year (7.19 2.0 versus 4.9 9 1.1 l/min, P = 0.002; 3.69 1.1 versus 2.69 0.5 l/min per m 2 , P= 0.009). Right atrial and pulmonary arterial mean pressure (mmHg) were lower with total orthotopic heart transplantation at 2 weeks (69 4 versus 99 5, P =0.04; 2293 versus 2597, P =0.1) and 1 year (5 92 versus 793, P =0.02; 1994 versus 259 7, P= 0.03). Pulmonary capillary wedge pressure (mmHg) was borderline nonsignificant (11 94 versus 13 97 at 2 weeks, 8 93 versus 14 95 at 1 year, P=0.055), as well as pulmonary vascular resistance (1.9 91 versus 2.59 1 at 2 weeks, 1.59 0.6 versus 2.79 1.7 WU at 1 year, P=0.051). Conclusions: Total orthotopic heart transplantation improves cardiac output and index in pts with high preoperative pulmonary vacular resistance. There is a lower mean RA and PA pressure perhaps due to less tricuspid and mitral regurgitation. In view of the frequently observed restrictive filling pattern after cardiac transplantation, total orthotopic heart transplantation can be beneficial until this pattern has subsided by preserving atrioventricular synchrony and offering better atrial transport. © 1997 Elsevier Science B.V.