Gary Y. Ott

Cardiac allografts from high-risk donors: Excellent clinical results☆

Rising waiting list mortality and increasing demand for donor organs have led to extension of traditionally accepted criteria for evaluation of cardiac grafts. From December 1985 to June 1992, 188 cardiac grafts were orthotopically transplanted into 178 recipients. Of these grafts, 38.3% (72/188) were defined as high-risk donors. Risk criteria included prolonged cardiopulmonary resuscitation, age greater than 40 years, high inotrope requirements, undersizing by more than 20% body weight, significant wall motion impairment by echocardiography, elevation of myocardial enzyme levels, and cold ischemia time greater than 4 hours. There were no recipient deaths attributable to primary graft failure in the perioperative period. Operative (30-day), 1-year and 5-year survival was 95.5%, 86.1%, and 77.3%, respectively, in the high-risk group compared with 93.7%, 86.0%, and 67.2%, respectively, in the low-risk donor cohort (p = 0.94). Comparison of duration of postoperative inotrope use, intensive care unit stay, total hospital stay, and in-hospital costs revealed no significant trends favoring either group in postoperative morbidity. Among long-term survivors, development of graft coronary disease was noted in 47.1% (24/51) of the high-risk donor group and only 17.4% (12/69) of the remaining group (p = 0.0005). Left ventricular ejection fractions in the high risk donor group were 0.58 +/- 0.01 at 2 years. Review of this series suggests that selective use of apparently compromised cardiac donors is compatible with excellent cardiac function and survival. Higher incidence of graft vasculopathy may cause significant morbidity during late follow-up.

Optimal electrode position for transvenous defibrillation : a prospective randomized study

OBJECTIVES This study was performed to determine the optimal position for the proximal electrode in a two-electrode transvenous defibrillation system. BACKGROUND Minimizing the energy required to defibrillate the heart has several potential advantages. Despite the increased use of two-electrode transvenous defibrillation systems, the optimal position for the proximal electrode has not been systematically evaluated. METHODS Defibrillation thresholds were determined twice in random sequence in 16 patients undergoing implantation of a two-lead transvenous defibrillation system; once with the proximal electrode at the right atrial-superior vena cava junction (superior vena cava position) and once with the proximal electrode in the left subclavian-innominate vein (innominate vein position). RESULTS The mean (+/- SD) defibrillation threshold with the proximal electrode in the innominate vein position was significantly lower than with the electrode in the superior vena cava position (13.4 +/- 5.7 J vs. 16.3 +/- 6.6 J, p = 0.04). Defibrillation threshold with the proximal electrode in the innominate vein position was lower or equal to that achieved in the superior vena cava position in 75% of patients. In patients with normal heart size (cardiothoracic ratio < or = 0.55), the improvement in defibrillation threshold with the proximal electrode in the innominate vein position was more significant than in patients with an enlarged heart (innominate vein 13.0 +/- 6.5 J vs. superior vena cava 17.9 +/- 5.1 J, p < 0.01). In patients with an enlarged heart, no difference between the two sites was observed (innominate vein 13.9 +/- 4.5 J vs. superior vena cava 13.6 +/- 8.3 J, p = NS). CONCLUSIONS During implantation of a two-lead transvenous defibrillation system, positioning the proximal defibrillation electrode in the subclavian-innominate vein will lower defibrillation energy requirements in the majority of patients.

HLA-DR mismatching correlates with early cardiac allograft rejection, incidence, and graft survival when high-confidence-level serological DR typing is used.

To determine if cardiac allograft outcome is improved among patients with fewer HLA-DR mismatches with their donors, we studied 132 recipients of a primary cardiac allograft who were transplanted between December 1985 and December 1991. These recipients and their donors all had high-confidence-level serological HLA-DR typing, previously shown to correlate highly with DNA DR typing. Patients were divided in two groups based on the HLA-DR mismatch with their donors. Group I consisted of 78 patients with 1 or zero DR mismatch and group II of 54 patients with 2 DR mismatches. Allograft outcome measurements included incidence of moderate rejection, incidence of allograft vasculopathy at 12 months, cardiac function measured as left ventricular ejection fraction (LVEF) and cardiac index (CI), and actuarial graft survival up to 7 years. Groups I and group II were not different with regard to recipient age, donor age, ischemia time, pulmonary vascular resistance, sex, or PRA greater than 0%. Group II had a higher incidence of moderate rejection on the first-week biopsy (47% vs. 25%, P = 0.019), and during the first month (84% vs. 58%, P = 0.006), but no difference was found in frequency of rejection from months 2 to 12. LVEF was not different in the groups at any point. CI was better in group I at 12 months (2.76 vs. 2.5, P = 0.03). No statistically significant difference was found in incidence of allograft vasculopathy (17% vs. 26%, P = 0.204). Actual graft survival at 1 year was better for group I (91% vs. 74%, P = 0.008), and actuarial graft survival at 6 years also favored group I (76% vs. 56%, P = 0.04). Using high-confidence-level serological HLA-DR typing assignments we demonstrated that HLA-DR mismatching correlates highly with cardiac allograft outcome. Implications are that heart transplant survival could be improved if prospective matching were feasible and prioritized or if immunosuppression were tailored to the HLA-DR match.

Cleft in the Anterior and Posterior Leaflet of the Mitral Valve: A Rare Anomaly

A rare entity that causes congenital mitral regurgitation is an isolated cleft mitral valve. The cleft in the mitral valve can be seen in either the anterior or posterior leaflet of the valve. We present a unique case of an individual with a history of congenital mitral regurgitation caused by a cleft in both the anterior and posterior leaflets of the mitral valve.

Gastrointestinal complications after orthotopic cardiac transplantation

OBJECTIVE AND METHODS A retrospective chart review was performed on all patients undergoing orthotopic cardiac allograft transplant at Oregon Health Sciences University. Our purpose was to evaluate the incidence of gastrointestinal complications in these patients, and to assess the effect of immunosuppression. RESULTS From December, 1985, to June, 1994, 240 recipients underwent 250 orthotopic cardiac allograft transplants at Oregon Health Sciences University with a 30 day mortality of 15 patients (6.3 +/- 3.0%). Of the 225 operative survivors, the follow-up ranges from 1.0 month to 8.8 years with a mean of 39.9 +/- 1.9 months. In our population of late survivors, 21 recipients (9.3%) have had gastrointestinal complications (GIC). Hepatobiliary (29%), peptic ulcer (14%), and pancreatic (14%) complications were the most prevalent. Surgical intervention was required in 19 patients (90%). Twelve procedures (63%) were either emergently or urgently performed, and seven procedures (37%) carried out electively. Operative mortality was 33% in those patients with an emergent or urgent intervention. There was no operative mortality among those who had an elective procedure. CONCLUSION Maintenance prednisone dose was higher in patients with GIC than in those patients without GIC, 16.1 +/- 2.5 mg versus 7.3 +/- 0.2 mg (P = 0.001), respectively. However, immunosuppression therapy for rejection episodes (i.e., Solumedrol megapulse or OKT3 therapy) was not related to an increased incidence of GIC. We present a review of our 21 cardiac transplant recipients to emphasize the potential for severe GIC and their corresponding perioperative morbidity and mortality.

Surgical management of traumatic aortic disruption

BACKGROUND Acute traumatic disruption of the descending thoracic aorta is a life-threatening injury that requires emergent operative intervention. From May 1988 to August 1996, 27 patients have undergone surgical repair at our institution. METHODS Diagnosis of aortic disruption was confirmed in all patients by aortogram prior to aortic repair. A Gott shunt was used in 24 patients (89%) and partial femoral-femoral bypass in 1 patient (4%) for distal perfusion. A clamp-and-sew technique was used in 2 patients (7%). RESULTS Mean aortic clamp time was 44 +/- 3 minutes (range 22 to 80 minutes) in patients with distal perfusion via a Gott shunt. One patient (4%) died within 30 days of aortic repair due to multisystem organ failure. Paraplegia occurred in 1 patient (4%). CONCLUSIONS With a disciplined, diagnostic and surgical approach for patients with traumatic disruption of the descending thoracic aorta, it is possible to achieve excellent outcomes. The use of a Gott shunt is a simple and effective method for distal perfusion during the repair of traumatic aortic rupture.

Purine efflux from transplanted human cardiac allografts : correlation with graft function

Purine efflux from transplanted human cardiac allografts was investigated as a potential biochemical correlate to graft preservation and eventual function. Coronary sinus effluent from 14 allografts was sampled at 1, 5, 10, 15, 20, and 25 minutes after reperfusion. The plasma fraction from each sample was analyzed for hypoxanthine, xanthine, urate, inosine, and adenosine by high-performance liquid chromatography. Total organ preservation time, aortic crossclamp and bypass times, and initial cardiac index off bypass were recorded. An inotropic score was calculated from the dosages of inotropic agents each recipient required immediately after transplantation. Inosine and adenosine were not detectable in the coronary sinus effluent at any time during reperfusion. Hypoxanthine concentration rose sevenfold (p < 0.001) 1 minute after reperfusion. Xanthine concentration peaked later at 5 minutes after reperfusion, a twofold increase (p < 0.02). As reperfusion continued, hypoxanthine and xanthine concentrations returned toward baseline levels. The rise in coronary sinus xanthine concentration provides evidence for hypoxanthine degradation by xanthine oxidase during the immediate reperfusion period. The extent of hypoxanthine efflux correlated with total graft ischemic time (p < 0.05), inotropic score (p < 0.005), and the time from crossclamp release to cessation of bypass (p < 0.01). Hypoxanthine efflux can be used as a sensitive and objective biochemical indicator of graft preservation and immediate function.