Randall Genton

Quantitative ultrasonic tissue characterization with real-time integrated backscatter imaging in normal human subjects and in patients with dilated cardiomyopathy.

We have shown previously that the physical properties of myocardium in dogs can be characterized with quantitative ultrasonic integrated backscatter and that interrogation of the tissue with ultrasound can delineate cardiac cycle-dependent changes in ultrasonic backscatter in normal tissue that disappear with ischemia and reappear with reperfusion if functional integrity is restorable. To determine whether this approach can be applied to man, we implemented an automatic gain compensation and continuous data acquisition system to characterize myocardium with quantitative ultrasonic backscatter and to detect cardiac cycle-dependent changes in real time. We developed a two-dimensional echocardiographic system with quantitative integrated backscatter imaging capabilities for use in human subjects that can automatically differentiate ultrasonic signals from blood as opposed to those obtained from tissue and adjust the slope of the gain compensation appropriately. Real-time images were formed from a continuous signal proportional to the logarithm of the integrated backscatter along each A-line. In our initial investigation, 15 normal volunteers (ages 17 to 40 years, heart rates 44 to 88 beats/min) and five patients with dilated cardiomyopathy (ages 22 to 52, heart rates 82 to 120 beats/min) were studied with conventional parasternal long-axis echocardiographic views. Diastolic-to-systolic variation of integrated backscatter in the interventricular septum and left ventricular posterior wall was seen in each of the normal subjects averaging 4.6 +/- 1.4 dB (SD) and 5.3 +/- 1.5 dB (n = 127 sites), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

An analysis of the effect of age on survival after heart transplant

BACKGROUND Advances in immunosuppression and reports of improved survival after cardiac transplantation have led to a liberalization of traditional recipient eligibility criteria, especially age. While age alone is not a contraindication to transplantation, conflicting data exists regarding long-term survival of the older transplant recipient. METHODS One hundred-fifty three patients undergoing consecutive first time cardiac transplantation from June 7, 1985 through February 1, 1997 were studied. For purposes of analysis, patients were stratified according to age (<55 years vs. >55 years) and hospital and late outcomes determined. RESULTS The incidence of early and late acute cellular rejection was not different based up on age. The freedom from infection at 12 months was 54+/-5% for patients < or =55 compared to 32+/-8% for patients >55 years old (p = .04). Five year estimated survival for patients >55 years old was only 56+/-9% compared to 78+/-5% for patients < or =55 years old (p = .005). The hazard for death was highest within the first post-transplant year for older patients and was most commonly due to infection. Both advanced age and pre-transplant diagnosis of ischemic cardiomyopathy were found to be independently and additively predictive of reduced late survival. CONCLUSIONS In the present study, late survival was adversely influenced by advanced age. Older patients (>55 years) with pre-transplant diagnosis of ischemic cardiomyopathy were particularly at high risk (risk ratio 4.6:1) for death. Given little prospect of expanding the number of donor hearts, careful selection of patients over the age of 55 with pre-transplant ischemic cardiomyopathy is warranted.

Circulatory support with a centrifugal pump as a bridge to cardiac transplantation

Since January 1985, the Heart Transplant Program at Washington University Medical Center, St. Louis, has performed 89 heart transplantations in 86 patients. Twenty patients (23%) have required preoperative mechanical support of circulation or respiration prior to transplantation. The Bio-Medicus centrifugal pump (Bio-Pump) formed the basis of our circulatory support system during the period of this report. Nine patients were placed on the Bio-Pump with the intention of bridging them to transplantation. Six patients required left ventricular assistance; in 2, the device was inserted because they could not be weaned from cardiopulmonary bypass. Two patients required biventricular assistance, 1 because she could not be weaned from cardiopulmonary bypass at the end of a cardiac operation. Extracorporeal membrane oxygenation was necessary in 1 patient for right ventricular decompensation and cardiac arrest four hours after orthotopic cardiac transplantation. One of these 9 patients died on circulatory support, and in another, a complication developed that precluded transplantation. The remaining 7 patients (78%) underwent a successful transplant procedure after an average of 1.6 days of circulatory support (range, 0.5 to three days), and all are long-term survivors of transplantation. There has been 1 late death at 17 months from a cerebrovascular hemorrhage. In summary, the centrifugal pump provides excellent short-term circulatory support for individuals who would otherwise die before cardiac transplantation.

Cardiac catheterization in patients with end-stage liver disease: Safety and outcomes†

Introduction: Patients with end‐stage liver disease (ESLD) awaiting transplant are at increased risk of bleeding. Nevertheless, these patients routinely undergo cardiac catheterization for various indications. Safety and outcomes of cardiac catheterization in these patients are not well reported. Methods: In a case–control study 43 patients with ESLD who underwent angiography for liver transplant work‐up were compared to 43 age and gender‐matched controls with no liver dysfunction. In‐hospital outcomes and procedural variables were compared. Results: Patients with ESLD had a lower baseline hemoglobin (12.1 ± 2.1 vs. 13.7 ± 1.8, P < 0.0005), lower platelet counts (86.8 ± 66 vs. 247 ± 80, P < 0.0001) and higher international normalized ratio (INR) (1.4 ± 0.2 vs. 1.1 ± 0.2, P < 0.0001) than controls. Among ESLD group, five (11.6%) patients received platelet transfusions, one received blood transfusion, and three patients (7%) with INR > 1.6 received fresh frozen plasma (FFP) compared with none in the control group. Smaller size (four French) vascular sheaths were used more frequently in the group with ESLD (16% vs. 4%, P = 0.04). There were no significant vascular or bleeding complications in either group. Conclusions: Elective cardiac catheterization can be safely performed in patients with ESLD with outcomes (vascular and bleeding complications, length of hospital stay and in‐hospital mortality) similar to patients without liver disease despite significant thrombocytopenia and elevated INR in patients with ESLD. Practices such as platelet transfusion for platelets <60,000 μL, prophylactic FFP transfusion for INR ≥≥ 1.6, less frequent use of antiplatelet therapy and more frequent use of smaller vascular sheaths may have contributed to the safety of cardiac catheterization in ESLD patients.

The Changing Face of Cardiac Transplantation: The Washington University Program, 1985-1987

Since January, 1985, 59 patients have undergone 62 heart transplantations at Washington University School of Medicine. The experience in this program serves as a useful microcosm of the field of cardiac transplantation as a whole to demonstrate certain trends that are becoming evident. Of the patients, 47% had coronary artery disease compared with 40% with cardiomyopathy. Fourteen patients (24%) were 55 years old or older at the time of transplantation. Sixteen patients (27%) required mechanical support of respiration or circulation or both prior to transplantation. Six patients were maintained with a left ventricular or biventricular assist device, and all survived; 1 patient received extracorporeal membrane oxygenation and lived; 7 patients were maintained with an intraaortic balloon pump, 6 of whom survived; and 2 were maintained with a mechanical ventilator and survived. The preoperative waiting period averaged 51 days for the group as a whole. Status-3 patients experienced an average 81-day waiting period, and those in blood group O waited 155 days. In contrast, critically ill patients (status 0) underwent transplantation within an average of 9 days. Actuarial survival at 12 months for all patients, operative survivors, patients age 55 years old or more, and patients bridged to transplantation was 87%, 92%, 84%, and 87%, respectively. Utilizing the combination therapy of cyclosporine, azathioprine, and prednisone introduced by one of us in 1983 and administered to all patients in this series, 50% of patients were rejection free and 56% were infection free at 12 months.(ABSTRACT TRUNCATED AT 250 WORDS)