Retrocaval passage of coronary bypass grafts to the inferior left ventricle wall.

Revascularization of the inferior side of the left ventricle is performed most often with aortocoronary free grafts. This article describes a technical improvement for anatomical fit and gain of length of these grafts by directing them to the right side of the heart after a passage behind the inferior vena cava.

Does bilateral internal thoracic artery grafting increase surgical risk in diabetic patients?

BACKGROUND: The purpose of this study was to determine whether, with appropriate techniques, diabetic patients could benefit from the advantages of double internal thoracic artery (ITA) coronary bypass without an increased hospital risk. METHODS: Between January 1990 and December 1996, 207 consecutive diabetic patients underwent coronary artery bypass graft operations. In 74 patients both arteries (bilateral ITA group) were used, whereas 133 patients received one ITA and vein grafts or vein grafts alone (nonbilateral group). Patients in the bilateral ITA group were younger (p<0.0001), predominantly male (p<0.0001), and were operated on more electively. The internal thoracic arteries were harvested by skeletonization without electrocautery, and strict glycemic control was pursued. RESULTS: No death was observed in the bilateral ITA group, whereas 7 patients died in the nonbilateral ITA group (p<0.05). Deep sternal wound infection was observed in 2 patients in the nonbilateral ITA group (1.5%) and in none of the bilateral ITA group (p = NS). There was no significant difference in the morbidity rate between the two groups except for greater blood losses in the bilateral ITA group. CONCLUSION: Double ITA coronary revascularization in young diabetic patients was performed without increased morbidity and mortality. The low rate of sternal wound infections may be related to ITA harvesting by a skeletonization technique, but larger studies are required to confirm these data.

Mechanical circulatory support towards the permanent implantation.

Experience on wearable LVAS Novacor support accumulated since the first implantation in March 1993, includes in November 1995, seven cases (six male, one female, mean age 34) of cardiogenic shock, unresponsive to optimal medical management referred for urgent transplantation. Post-implantation period was free of any major incident in all but one, allowing transplantation in five, on an elective basis, and prolongation of the waiting period, at home in two. This experience suggests that a major breakthrough in the technology of mechanical support has been achieved: patients awaiting transplantation can be discharged home, which is both the result and an contributing factor of a satisfactory quality of life. This improvement allows speculations on coming studies on permanent implantation of the wearable LVAS Novacor, as an alternative therapy to cardiac transplantation.

The gastrointestinal tract: an underestimated organ as demonstrated in an experimental LVAD pig model.

BACKGROUND: Although hemodynamic stability and renal function are important and are monitored closely in patients with implanted left ventricular assist devices (LVAD), the gastrointestinal tract may be underestimated in the early postoperative period with regard to adequate perfusion. We investigated renal, intestinal, and whole body metabolic changes in response to variations in LVAD flow and inspired oxygen concentration (FiO2). METHODS: Left ventricular assist devices were implanted in 10 adult pigs (weight, 55 +/- 1.76 kg). Renal vein (RV), superior mesenteric vein (SMV), and pulmonary artery (PA) blood oxygen saturation and lactate concentration were measured and used as tissue perfusion markers. These measurements were made at baseline and after changes in LVAD flow or FiO2. RESULTS: Oxygen saturation in the PA, SMV, and RV decreased significantly after a reduction in LVAD flow (P < 0.05), with a greater reduction in the SMV than in the PA and RV (p < 0.05 at LVAD flow 3.5L/min; p < 0.01 at LVAD flow 2.0 and 1.0 L/min). The lactate concentration in the PA and SMV increased significantly (p < 0.01) with decreased flow, with a greater increase in the SMV than in the PA (p< 0.05), whereas it remained unchanged in the RV. Oxygen saturation in the PA, SMV, and RV decreased significantly after a reduction in FiO2 (p < 0.05). Lactate concentration in the PA, SMV, and RV increased significantly at FiO2 of 0.10 (p < 0.05). Lactate concentration in the PA and SMV was significantly higher than that in the RV at Fi)2 of 0.10 (p < 0.01). CONCLUSIONS: The results show that the gastrointestinal tract is at high risk during low perfusion or low FiO2, whereas the kidneys' metabolic function appears to be less disturbed. In clinical practice, this emphasizes the need to ensure adequate blood flow and respiratory function, especially after extubation, in patients with implanted LVAD. This might avoid intestinal ischemia and subsequent endotoxemia. Gastrointestinal tonometry may help in the assessment of intestinal perfusion.

Mechanical bridge to transplantation: when is too early? When is too late?

BACKGROUND: Optimal timing of implantation of a mechanical circulatory support system in the treatment of acute cardiogenic shock is still unsettled. The issue has been addressed in a retrospective analysis of a group of 98 patients in cardiogenic shock refractory to medical therapy who were candidates for cardiac transplantation, admitted from 1987 to 1994. METHODS: The treatment included reinforced inotropic support by addition of phosphodiesterase inhibitors to sympathomimetic agents. The patients who did not improve were immediately brought to the operating room for mechanical circulatory support system implantation. RESULTS: The overall survival in the group of 28 patients selected for mechanical bridge is 50%. No predictive factors of death or multiorgan failure while on the device could be identified, suggesting a lack of contraindications to mechanical circulatory support system implantation. CONCLUSIONS: The high death rate in patients maintained on medical therapy because of initial improvement as they are awaiting transplantation suggests the benefit of a rapid semielective implantation of an intracorporeal device.

[Cardiac transplantation; results after 5 years]. / La transplantation cardiaque; résultats après 5 ans.

After cardiac transplantation, long-term results were assessed in a group of 46 patients who survived more than 5 years after surgery. They were the survivors (50%) of a group of 92 patients who underwent transplantation before January 1990. On January 1995, mean follow-up was 82 +/- 14 months. Quality of life was estimated satisfactory (mean score 8.4 +/- 2); 60% of the patients were active; 89% were class NYHA I or II. Nevertheless, several problems have been identified: rise in body weight for all, over 10 kg in 31%; hypertension, renal failure, considered to be severe (serum creatinine > 250 micrograms/l) in 26%, diabetes in 13%, osteoarthropathy in 33%, cancer in 6%, and, above all, chronic alteration of the coronary arterial bed in 53% of the patients. These problems reflect the immunological conflict and complications of immuno-suppression.

[Mechanical assistance of circulation. 42 cases]. / Assistance mécanique de la circulation. 42 observations.

OBJECTIVES: Mechanical circulatory support was proposed in patients in cardiogenic shock, as a bridge to cardiac transplantation or weaning. The aim of the present study is an analysis of the first 42 cases. METHODS: The 42 cases included 31 patients in cardiogenic shock unresponsive to medical therapy, good cardiac transplant candidates, and 11 patients unweanable off ventricular assist, or in shock in the intensive care unit. Results are evaluated in terms of transplantability and hospital survival. RESULTS: Overall success rate is 67%, ranging from 25% in previously transplanted patients to 46% following acute myocardial infarction and 57% in cardiomyopathy. Age and learning curve played a significative role. CONCLUSION: These data suggest that mechanical support improves survival in patients in cardiogenic shock. Earlier implantation should improve the patient outcome.

[What are the criteria of priority for the patient to be accepted on the waiting list for cardiac transplantation?]. / Quels critères de priorité pour l'inscription sur la liste d'attente d'un candidat à la transplantation cardiaque?

The limited resources (in grafts, human and financial resources) incited the authors to carry out a prospective assessment of the value of assessing adrenergic function (scintigraphy with meta- iodo- benzyl guanidine, MIBG) for the procedure of inscription on the waiting list of patients with cardiac failure awaiting cardiac transplantation. The study was undertaken from October 1988 to October 1992. Seventy-eight candidates for transplantation were included in the study. Forty-six patients with a MIBG cardiothoracic ratio less than 120% were placed on the waiting list. In July 1993, 35 had undergone transplantation after a 5 months delay. Four patients are still awaiting transplantation and 7 died whilst on the waiting list. Thirty two with a MIBG cardiothoracic ratio greater than 120% were treated medically: in 14 cases (43%) this decision was reviewed after 17 +/- 12 months. The clinical course was stable in the other 18 patients with a follow-up of 46 +/- 18 months (range: 12-72 months). In all, the results of this study show that a procedure of selection for inscription on the waiting list of patients with cardiac failure judged to be good candidates for transplantation based on the value of the MIBG cardiothoracic ratio allows deferrement of inscription of patients at least risk without changing the chances of survival in the whole population group within a 2 year period.

Orthotopic cardiac transplantation with direct caval anastomosis: is it the optimal procedure?

Total excision of the right atrium with a minimal cuff of left atrium remaining around the four pulmonary veins, followed by direct anastomoses on venae cavae, has been proposed as an alternative to the standard procedure described by Shumway and Lower for orthotopic cardiac transplantation. To investigate whether this "anatomic" transplantation should be proposed as the optimal procedure, we prospectively randomized 78 patients having 81 procedures since 1991 into two groups: group I, standard transplantation (n = 40), and group II, "anatomic" transplantation (n = 41). The two groups were statistically similar in recipient age, sex, weight, disease, and status at the time of transplantation. Also similar were donor age, sex, weight, and drug dependency at the time of harvesting. All patients could be weaned from cardiopulmonary bypass with comparable graft ischemic times (group I, 136 +/- 46 minutes; group II, 138 +/- 51 minutes). Immediate recovery of sinus rhythm occurred in 20 cases of group I and 36 cases of group II. Delayed recovery of sinus rhythm in the first postoperative week occurred in 15 cases of group I and 5 cases of group II. Persistence of atrial arrhythmia occurred in 5 cases of group I and never in group II. These differences were highly significant (p < 0.001). Postoperative hemodynamics showed a higher cardiac index at day 1 in group II (4.12 +/- 0.85 L/min per square meter) than in group I (3.77 +/- 0.65 L/min per square meter) (p = 0.04). There were 13 early deaths in group I and 8 early deaths in group II. One death in group I was related to an acute atrioventricular block at 3 weeks with no evidence of cardiac rejection at histologic examination. Two patients in group I (5%) required definitive pacemaker implantation for prolonged sinus node dysfunction. Echocardiographic and Doppler studies of survivors have been performed 2 to 3 months after transplantation. Right atrial area was significantly reduced (p < 0.01) in group II (18 +/- 4.7 cm2) versus group I (24 +/- 7 cm2), as was left atrial area (group I, 24 +/- 4.5 cm2; group II, 20 +/- 5 cm2) (p = 0.01). Mild tricuspid regurgitation was observed in 82% of group I patients versus 57% of group II patients (p < 0.05), inasmuch as mitral regurgitation was comparable (71% in group I, 67% in group II).(ABSTRACT TRUNCATED AT 400 WORDS)

Direct mechanical assistance of the right ventricle with the Hemopump in a porcine model.

In 6 pigs, a 14F Hemopump was placed through the pulmonary artery into the right ventricle. The pulmonary artery was banded proximal to the outflow port of the Hemopump, and tightening the band increased right ventricular peak systolic pressure by 50%. There were significant falls in right ventricular stroke volume (from 43 +/- 7.3 mL [+/- the standard deviation] to 27 +/- 8.0 mL; p < 0.001) and cardiac output (from 4.94 +/- 0.76 L/min to 3.70 +/- 0.95 L/min; p < 0.01) and increases in right ventricular peak systolic pressure (from 28 +/- 9.7 mm Hg to 42 +/- 17.1 mm Hg; p < 0.01) and end-diastolic pressure (from 2 +/- 0.8 mm Hg to 12 +/- 6.4 mm Hg; p < 0.02). Mean aortic pressure fell (from 65 +/- 29.9 mm Hg to 61 +/- 9.6 mm Hg; p < 0.01), but systemic vascular resistance was unchanged, thus indicating a fall in left ventricular output reflected by a decrease in mixed venous oxygen saturation (from 60% +/- 8.9% to 47% +/- 7.6%; p < 0.01). After 15 minutes with the Hemopump at maximum speed, these variables returned to control levels (stroke volume, 38 +/- 4.5 mL; cardiac output, 4.50 +/- 0.63 L/min; right ventricular peak systolic pressure, 29 +/- 8.3 mm Hg; right ventricular end-diastolic pressure, 4 +/- 2.0 mm Hg; mean aortic pressure, 72 +/- 10.4 mm Hg; mixed venous oxygen saturation, 56% +/- 4.6% [all, p = not significant versus controls]).(ABSTRACT TRUNCATED AT 250 WORDS)

Bridge to transplantation with the wearable Novacor left ventricular assist system: operative technique.

Although the outcome of patients transplanted after univentricular cardiac support is similar to that of conventional patients, death on the device remains a substantial problem. The wearable Novacor left ventricular assist system (LVAS) may offer advantages over console-based systems by improving rehabilitation before transplantation. For these advantages to be realised, however, a smooth perioperative course is necessary. We describe our operative technique, based on minimising blood loss and preserving right ventricular function, and the results in the first three patients to have the wearable Novacor LVAS implanted in this institution.

[Cardiac surgery in chronic hemodialysed patients: immediate and long-term results]. / Chirurgie cardiaque chez l'hémodialysé chronique: résultats immédiats et à long terme.

Between 1979 and 1993, 50 patients (33 men and 17 women) receiving chronic haemodialysis, underwent 53 cardiac surgical procedures in the department. The mean age was 56 +/- 13 years. The average duration of preoperative dialysis was 82 +/- 63 months. The average duration of cardiac symptoms before surgery was 35 +/- 52 months. Twenty-seven patients (54%) were in NYHA functional classes III or IV before surgery. Sixteen patients (32%) had preoperative left ventricular ejection fractions of less than 0.40. Twelve patients (24%) were emergency referrals. Twenty-nine patients underwent isolated coronary bypass surgery, 13 patients underwent isolated aortic valvular replacement which had to be repeated in one case, 3 patients underwent mitral valve replacement, which had to be repeated in 2 cases, and 5 patients underwent combined surgery. The average aortic clamping time was 75 +/- 32 minutes, the average cardio-pulmonary bypass time was 125 +/- 50 minutes. The surgical revascularisation of the coronary patients was incomplete in 37% of cases because of the severity of the underlying coronary artery disease. The average postoperative bleeding was 800 +/- 650 ml; 29 patients (58%) were transfused with an average of 4.3 +/- 3 units of blood. The global early mortality was 9 patients (18%); 10% in coronary bypass, 7% in aortic valve replacement and 50% in patients with more complex procedures. The causes of death were cardiac (n = 4), sepsis (n = 2) and multiple organ failure (n = 3). The morbidity was 39%, mainly due to low cardiac output.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical implantation of the wearable Baxter Novacor ventricular assist system.

Implantation of the wearable Novacor electrically powered left ventricular assist system was performed on March 16, 1993, in a 44-year-old man hospitalized for an acute episode of myocardial decompensation after a 6-year history of dilated cardiomyopathy. He was rehabilitated fully and became ambulatory, awaiting a suitable cardiac graft for 59 days. He is now back to work, enjoying a normal life. This case illustrates the progress made by miniaturization of the external components of the system. General acceptance of the system and psychological adaptation to the new way of life were remarkable.

Use of the Nippon-Zeon pneumatic ventricular assist device as a bridge to cardiac transplantation.

The Nippon-Zeon (NZ) ventricular assist device is a sac type, air driven, heterotopic, external pump. Its performance has been evaluated in Japan as a bridge to myocardial recovery. Few data are available on the device as a bridge to heart transplantation. Since 1991, 10 patients (9 men) were bridged to heart transplantation with NZ, all in biventricular support. The mean age was 39 +/- 13 years (range, 21-60 years), mean body weight was 75 +/- 13 kg (range, 51-95 kg). Five patients had a dilated cardiopathy, and five were ischemic (three acute myocardial infarctions). Despite maximal inotropic support, including enoximone in seven, epinephrine in three, and intraaortic balloon pumping in one, eight patients were anuric, three were in acute hepatic failure, and three were intubated. Preoperative hemodynamic and biologic values were: cardiac index, 1.57 +/- 0.4 l/min/m2; pulmonary capillary wedge pressure, 34 +/- 5 mmHg; creatinine, 200 +/- 80 mumol/l; blood urea nitrogen, 17.5 +/- 8 mmol/l; total bilirubin 36 +/- 6 mumol/l; aspartate aminotransferase, 1,000 +/- 2,000 IU/l. In all patients, a biventricular assist device was implanted without the use of cardiopulmonary bypass. Improvement occurred immediately in all but one. Mean left ventricular flow was 4.5 +/- 0.8 l/min. Anticoagulation was maintained with intravenous heparin. Recently for bleeding was required in one case (10%), and two patients had positive blood cultures that were successfully treated. There was no mechanical failure. Hemolysis was not significant (lactate dehydrogenase, 378 +/- 50 IU/l; plasma-free hemoglobin below 10 mg/dl). Each device was free of thrombi and deposits at time of explantation. One patient died while on assist. Nine patients (90%) were transplanted after 11 +/- 8 days (range, 1-32 days). Three died early after transplantation, one of graft failure, two of sepsis. Six patients (66%) could be discharged. The follow-up ranges from 7 to 28 months. NZ is a simple, reliable, pneumatic device driven by a light, silent console; it can be rapidly implanted without cardiopulmonary bypass in patients in desperate condition who are awaiting cardiac transplantation. The difficulty of patient rehabilitation while using this device should limit the duration of support to weeks to allow the patient to be in optimal condition for heart transplantation.

Right heart function during left ventricular assistance in an open-chest porcine model of acute right heart failure.

Changes in the right ventricular function measured with a thermodilution ejection fraction catheter have been recorded in open-chest normal pigs and pigs with acute right heart failure (RVF) undergoing left ventricular assistance with a pneumatic-sac-type device (LVAD). To produce acute right heart failure, 5 pigs underwent ligation of the right ventricular free wall coronary arteries. Compared with normal pigs, cardiac output in ligated pigs fell by 21% (7.5 +/- 0.5 vs 9.5 +/- 1.2 L/min; p < 0.05) and the right ventricular end diastolic pressure rose (11.4 +/- 2.6 vs 5.7 +/- 3.6 vs mmHg: p < 0.05). With the left ventricular assist device connected, the right atrial pressure was increased to 3, 5, 7, 10 and 12 mmHg by volume loading while maintaining the haematocrit at 35 +/- 6%. The right ventricular stroke work index (RVSWI) increased with volume loading in normal pigs. In RVF pigs, RVSWI increased significantly with the LVAD (59.2 +/- 5.8 vs 23.5 +/- 7.8 mmHg ml/min/kg, p < 0.01), approaching that of normal pigs (62.3 +/- 4.8 mmHg ml/min/kg). Similar changes were observed in the cardiac output and right ventricular stroke volume. These results show that, in this model of open-chest, mild, acute right heart failure, left ventricular assistance allows right ventricular function to return to normal, despite volume overloading, by decreasing right ventricular after load and increasing right ventricular compliance.

Donor/recipient aorta size mismatch in heart transplantation: a technical alternative.

A technical alternative is proposed to enable transplantation in cases of considerable size mismatch between donor and recipient aorta: interposition of a Dacron graft of intermediate diameter. This procedure was performed in a 56-year-old patient weighing 75 kg in whom a heart from a 40-kg donor was implanted.

Mitroflow pericardial valve: long-term durability.

Isolated aortic (n = 107), mitral (n = 63), and tricuspid (n = 1) valve replacement and 28 double-valve replacements were performed with a second generation of pericardial valves, the Mitroflow valve, in 199 patients from March 1983 to December 1986. Follow-up (total, 1,058 patient-years) was extended to 106 months and 91.5% complete. Mean age was 58 +/- 13 years. The operative mortality included 22 deaths, non-cardiac-related in 7. The actuarial probability of survival for all patients was 66% +/- 4% at 8.5 years. There were no significant differences between patients with aortic valve replacement, mitral valve replacement, or double-valve replacement. The rate of thromboembolic events, antithromboembolic therapy-related hemorrhage, periprosthetic leak, and endocarditis is extremely minimal. Structural valve dysfunction occurred at a rate of 3.2% +/- 0.5%/patient-year. Actuarial freedom from the event was 94.6% +/- 1.7% at 5 years and 63.7% +/- 6.5% at 8.5 years for all valves. There were no difference in structural valve dysfunction rate between patients having aortic, mitral, or double-valve replacement. Thirty-five patients were reoperated on (3.4 +/- 0.6%/patient-year for all). The rate of all valve-related morbidity and mortality was 5.6% +/- 0.7%/patient-year for all patients, actuarial freedom from the event being 44% +/- 7% at 8.5 years. These data suggest that the excellent hemodynamic characteristics of the valve are balanced by a risk of valve failure that is slightly increased when compared with porcine valves.

Preservation of the aortic valve in acute aortic dissection: long-term echocardiographic assessment and clinical outcome.

The aim of the present study was to determine the long-term status of the native aortic valve after surgical treatment of acute aortic dissection involving the ascending aorta. From 1972 to 1991, 93 patients underwent operation for type I or II aortic dissection. There were 76 men and 17 women. Mean age was 54 +/- 13 years. Eighty patients (86%) had a conservative procedure regarding the aortic root and aortic cusps: 74 had prosthetic replacement of the ascending aorta and 6, complete replacement of the aortic arch. Thirteen patients (14%) had simultaneous replacement of the aortic valve and the ascending aorta. The overall hospital mortality rate was 29% (27/93). The overall actuarial survival rate was 60.2% +/- 5.2%, 49.7% +/- 6.1%, and 35.9% +/- 8.1% at 5, 10, and 15 years, respectively. The survival rates for patients who had an ascending aortic procedure only were 63% +/- 5.5%, 54% +/- 6.5%, and 39% +/- 8.5% at 5, 10, and 15 years, respectively, and for patients who required aortic valve replacement, 45% +/- 14% and 22% +/- 17.5% at 5 and 10 years, respectively. Fifty long-term survivors (94% follow-up) with preservation of the aortic valve and aortic root were studied. Among them, 9 (18%) died within a mean interval of 97 +/- 46 months after operation. Causes of death were ischemic cardiac failure (2), aortic rupture or extension of dissection (4), renal disease (1), stroke (1), and sudden death (1). Forty-one patients had long-term clinical and echocardiographic evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacological bridge to cardiac transplantation: current limitations.

Addition of intravenous enoximone to sympathomimetic agents permits a rapid and drastic improvement in the clinical and hemodynamical condition of patients in cardiogenic shock referred for a mechanical bridge to transplantation. The present experience, based on the management of 52 patients, permits us to point out the current limitations of this pharmacological bridge: the rate of sudden death, the incompleteness of the physical rehabilitation of the patients, and the vanishing effect of intravenous enoximone.