Extracorporeal membrane oxygenation for adult cardiac support: the Allegheny experience.

BACKGROUND: A mix of cardiac assist options is necessary to meet the diverse indications for cardiac support in a comprehensive heart failure program. At our institution, an adult extracorporeal membrane oxygenation (ECMO) system comprising a centrifugal pump and hollow fiber membrane oxygenator is used for short-term and temporary cardiac assist. METHODS: Between December 1991 and August 1997, 82 adult cardiac patients were supported on ECMO. Indications for cardiac assist included postcardiotomy cardiogenic shock (PCCS, 55 patients), high-risk cardiology intervention (27 patients), perioperative cardiac graft failure (4 patients), and emergency cardiac resuscitation (6 patients). Data for analysis were collected by prospective completion of standardized ECMO report forms and retrospective review of hospital charts. RESULTS: The ECMO system was inexpensive to operate, uncomplicated to implant, and adaptable for diverse indications. Survival in PCCS was 20 of 55 patients (36%), with an increased survival rate of 56% (18 of 32 patients) in patients with PCCS after isolated coronary bypass. Catheter-based revascularizations were successfully performed in 26 of 27 (96%) high-acuity patients temporarily supported by ECMO, and 23 of 27 patients (85%) survived to discharge. Survival in the cardiac graft failure group was 2 of 4 (50%). No patient supported on ECMO for cardiac resuscitation survived. CONCLUSIONS: ECMO provides good cardiopulmonary and end-organ support; survival rates are similar to or higher than those seen with centrifugal pump support in comparable patient populations.

Hydrochloric acid inhalation: who needs admission?

Nine pharmaceutical workers were exposed to hydrochloric acid (HCl) fumes. Four were discharged with no symptoms after a 4 h observation period in the accident and emergency (A&E) department. The remaining five were admitted to the medical unit because of severe symptoms, reduced peak expiratory flow rate (PEFR), or hypoxaemia. Treatment was symptomatic and discharge followed 24 h later. Only one patient, discharged from the medical unit, developed long term airway hyper-reactivity, superimposed on a background of chronic obstructive airways disease. Thus patients who are minimally symptomatic with normal PEFR and oxygen saturation values can be safely discharged from the A&E department after a short observation period of 4 h with advice to return if dyspnoea occurs. Caution should be employed in severely symptomatic patients, those with pre-existing lung pathology or reduced PEFR, and hypoxaemic patients, where observation for at least 24 h is recommended.

Clinical cardiomyoplasty: review of the ten-year United States experience.

BACKGROUND: Clinical trials of dynamic cardiomyoplasty were pioneered at Allegheny General Hospital beginning in September 1985. Data from 9 years of experience with the procedure at this institution and more recent data from newer cardiomyoplasty centers have been analyzed for outcome analysis and future trends. METHODS: Each patient underwent a cardiomyoplasty procedure using the left or right latissimus dorsi muscle. Thirty-four patients were studied at Allegheny: 5 patients implanted with dual chamber pacemakers as single stimulus myostimulators, 11 patients composing the phase I Food and Drug Administration trial of the Medtronic burst myostimulator, and 18 patients entered in the phase II Medtronic trial. Patients from seven additional centers entered the phase II trial in 1991. Fifty-seven patients completed follow-up studies to 1 year after operation in this trial. RESULTS: Operative mortality was 5/57 (11%) in the American phase II group and 5/34 (15%) in the Allegheny group (1/18, 6% for Allegheny phase II). Nineteen patients (19/57, 33%) from the combined phase II population died in the first year, and 10/34 (29%) in the Allegheny study. The predominant cause of postdischarge death was arrhythmia (12/19, 63% American; 7/10, 70% Allegheny). In all groups significant improvement was seen in quality of life and functional class. Phase II patients demonstrated significant increases in ejection fraction and stroke work. CONCLUSIONS: Failure to sustain improvement and arrhythmia-related death are complex challenges for this procedure; however, realistic solutions have been proposed and are under investigation.

Clinical cardiomyoplasty: preoperative factors associated with outcome.

Dynamic cardiomyoplasty has been used clinically to augment the ventricular function of a failing heart. Fifteen clinical dynamic cardiomyoplasties have been performed at Allegheny General Hospital since 1985. Left ventricular ejection fraction improved in long-term survivors from a preoperative value of 0.23 +/- 0.02 to 0.32 +/- 0.05 with postoperative cardiomyostimulation (p < 0.05). There was an average reduction of 2 +/- 0.3 New York Heart Association classes (3.6 +/- 0.2 before operation versus 1.6 +/- 0.4 after operation; p < 0.001). Postoperative mortality was 27% (4/15), and early mortality (within 6 months after operation) was 20% (3/15). Significant preoperative differences between survivors and nonsurvivors were found in right ventricular ejection fraction (0.53 +/- 0.03 versus 0.30 +/- 0.07; p < 0.05), pulmonary artery mean pressure (19 +/- 2 versus 34 +/- 6 mm Hg; p < 0.05), pulmonary artery diastolic pressure (12 +/- 1 versus 25 +/- 5 mm Hg; p < 0.05), and pulmonary vascular resistance (1.4 +/- 2 versus 2.5 +/- 0.7 Wood units; p < 0.05). Dynamic cardiomyoplasty can be done with low operative mortality in patients with isolated left ventricular failure, but mortality is high in those with biventricular failure or pulmonary hypertension. Improvement in functional class and ventricular function can be expected in long-term survivors. Application of these findings to patient selection will improve the risk/benefit ratio for dynamic cardiomyoplasty.

Prolonged open sternotomy and delayed sternal closure after cardiac operations.

Maintenance of an open sternotomy (OS) after a complicated cardiac operation is an adjunct in the treatment of the severely impaired heart. We hypothesized that predictors of the timing, morbidity, and prognosis of delayed sternal closure (DSC) could be determined by intensive case review. Prolonged OS was used in 107 of 6,030 adult open heart patients (1.8%) between 1987 and 1991. Indications for OS were hemodynamic instability (40), myocardial edema (18), intractable bleeding (23), relentless arrhythmias (9), and ventricular assist devices (17). Delayed sternal closure was carried out in 75 of 107 patients at a mean of 3.4 +/- 0.3 days after OS. Fifty of these 75 (67%) survived and were discharged an average of 43 +/- 6 days after closure. Fifty-seven patients died: 32 before DSC at 3.7 +/- 0.8 days after OS and 25 after DSC at 27 +/- 4 days after OS. Baseline cardiac index (1.7 +/- 0.1 L.min-1.m-2) improved an average of 1.0 +/- 0.1 L.min-1.m-2 after OS (p less than or equal to 0.001) and remained stable through DSC (2.5 +/- 0.3 L.min-1.m-2) and late (9 +/- 0.7 days) follow-up (2.8 +/- 0.1 L.min-1.m-2). Delayed sternal closure in patients without ventricular assist devices was significantly more likely to be successful (45/63 versus 9/27; p less than 0.002) when carried out after the onset of a negative daily fluid balance. Sternal infection occurred in 4 of 75 (5%) patients after DSC and was associated with bleeding as an indication for OS (3/15 versus 1/60; p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Twenty-five-year review of the Magovern-Cromie sutureless aortic valve.

We reviewed 25 years (4,798 patient-years) of aortic valve replacement with the Magovern-Cromie sutureless valve. Operative mortality was 11% for isolated aortic valve replacement and 15% for aortic valve replacement with concomitant cardiac procedures. Since 1981, operative mortality has declined to 4.9%. Valve-related morbidity was in the lower expected ranges for prosthetic aortic valves: ball variance, 0.3%/patient-year; paraprosthetic leak, 0.41%/patient-year; valve endocarditis, 0.43%/patient-year; valve thrombosis, 0.04%/patient-year; and embolic events, 3.95%/patient-year. The incidence of aortic valve reoperation was 0.76%/patient-year. The 5-year, 10-year, and 20-year probability of survival corrected for normal mortality was 77%, 64%, and 52% for all discharged patients. This review confirms the Magovern-Cromie valve to be a safe, durable, and efficient prosthetic valve.

Bone resorption in osteogenic sarcoma--II. Resorption of the bone collagenous matrix by tumor cells, normal fibroblasts and macrophages.

Three osteogenic sarcoma cell lines of human and canine origin were compared to normal fibroblastic cells and peptone-induced murine peritoneal macrophages in terms of bone collagenous matrix (BCM) resorption capacity. The dissolution of the BCM was measured in an in vitro system consisting of the tested cells and live or killed [3H]-proline-labeled fetal mouse long bones. Experiments with osteogenic sarcoma cells revealed a paradoxical phenomenon indicating an inverse relationship between the number of tumor cells and the rate of collagen resorption from live bones. On the other hand, collagen matrix of devitalized bones, particularly those denatured by exposure to heat, is strongly resorbed by osteogenic sarcoma cells even in the presence of serum. Contrary to osteogenic sarcoma cells, normal fibroblasts do not resorb collagen from either live or killed bones, regardless of the devitalization method and culture conditions utilized. Macrophages resorb collagenous matrix from live bones, but their collagen resorption activity from devitalized bones depends greatly on choice of the incubation condition. Results have shown that osteogenic sarcoma tumor cells, when acting alone, may not have the capacity to destroy healthy bone. We suggest, therefore, that bone destruction seen in osteogenic sarcoma patients depends on the metabolic condition of the affected bone, and the interaction between the tumor and normal host cells and tissues.