Biomedical subjects
Publications and source records attributed to C H Van Meter.
Right heart failure continues to affect our clinical success with left ventricular assist device support. The inability to consistently predict the probability of the onset of right heart dysfunction contributes to this problem. We have developed an aggressive approach to the management of these patients in an attempt to decrease the incidence of this condition, which continues to carry a very high operative mortality.
Transmyocardial laser revascularization (TLR) was initially touted as a promising therapeutic alternative for tackling the growing problem of cardiac allograft vasculopathy in late heart transplant survivors. We first described 4- and 8-week observations of application of this surgical technique, in which we professed enthusiasm for TLR in providing symptomatic relief and in reducing ischemic burden. In this report, we present the long-term (24-month) impact of TLR on clinical outcome, channel patency, and recrudescence of ischemic burden. In the long term, surgical TLR provides neither consistent symptomatic improvement nor an ameliorative effect on the natural history of cardiac allograft vasculopathy.
Ventricular assist device programs can be structured in a variety of models and can make use of personnel derived from a broad spectrum of clinical and hospital-based practice. When aggressively and proactively negotiated with payers, these programs can be cost-effective and thoroughly self-sustaining.
BACKGROUND: Thyroid hormone level abnormalities commonly exist in severe heart failure and may be of prognostic value. The therapeutic potential of using thyroid hormone for cardiogenic shock resulting from progressive heart failure has not been previously delineated. We sought to evaluate the role of an intravenous infusion of thyroxine as an adjunct to conventional inotropic agents and intra-aortic balloon counterpulsation in patients with severe heart failure with cardiogenic shock. METHODS AND RESULTS: We studied 10 consecutive patients with severe systolic heart failure that progressed to a cardiogenic shock state unresponsive to conventional pharmacological inotropic measures. Intravenous thyroxine (20 micrograms/h) was used as an adjunctive salvage measure after the failure of conventional pharmacological and mechanical support by intra-aortic balloon pump. The invasive hemodynamic profile (right atrial pressure, pulmonary capillary wedge pressure, cardiac index, mean arterial pressure), overall clinical status, core temperature, renal function, and tachyarrhythmias were compared before and sequentially at 6, 24, and 36 hours after the initiation of thyroxine administration. Long-term outcome was also defined. All patients had statistically significant improvements in cardiac index, pulmonary capillary wedge pressure, and mean arterial pressure at 24 and 36 hours post-initiation of thyroxine. No sustained tachyarrhythmias were seen during the thyroxine infusion. In 9 of 10 patients who underwent left ventricular assist device placement and/or heart transplantation, the use of thyroxine served as an effective adjunctive measure to allow transitioning to definitive surgical therapy. The 6-month and 1-year cohort survival rates, achieved by the transition to surgical therapy, were 90% and 80%, respectively. CONCLUSION: The beneficial hemodynamic properties of intravenous thyroid hormone can be effectively used in otherwise terminal situations of cardiogenic shock, and in such situations, the use of thyroid hormone can serve as a pharmacological adjunct to a definite surgical intervention. Further studies in larger numbers of patients might be warranted to confirm these findings.
Administration of growth factors is emerging as a new therapeutic approach for the enhancement of collateral vessel formation in the ischemic heart. We have investigated the effects of intramyocardial delivery of FGF-2 in the presence and absence of heparin on angiogenesis in a porcine model of myocardial infarction. Yorkshire pigs were subjected to myocardial infarction by the placement of an embolization coil in the left anterior descending artery (n = 5). Four to five weeks after creation of an infarct, FGF-2 (10 micrograms) alone or in complex with heparin, heparan sulfate, or heparin agarose beads was injected either into the normal myocardium or along the infarct border area. Histologic evaluation of each injection site was performed 4 to 5 weeks post-injection. The effect of FGF-2 on angiogenesis was evaluated by determining the number of capillaries (diameter < 20 microns (and arterioles (> 20 microns with tunica media) in each area observed. The number of capillaries were not affected by the treatment of FGF-2 both in normal myocardium and infarct border area. However, in the normal myocardium, the number of arterioles were increased with the treatment of FGF-2 alone (85 +/- 59%, P < 0.04), FGF-2 plus heparin (281 +/- 193%, P < 0.004) and FGF-2-coated heparin beads (241 +/- 141%, P < 0.01), as compared to control. Delivery of FGF-2 into the infarct border area, also increased the number of arterioles when FGF-2 was given with heparin (736 +/- 154%, P < 0.001) or heparin beads (700 +/- 109%, P < 0.001), as compared to control. FGF-2 administered with heparin was the most effective method of enhancing angiogenesis as compared to FGF-2 alone, FGF-2 plus heparan sulfate, or FGF-2 coated heparin agarose beads.
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Continued experience with the TCI Heartmate Ventricular Assist System has led to improvements in our ability to avoid and manage right heart dysfunction during weaning from cardiopulmonary bypass. The advent of the electric device has intensified the need for these techniques because of its elevated minimal heart rate (50 beats/min) at start-up and the demands this places on the native right heart. We have developed and here describe a technique we have used successfully in our last 8 patients to assist in deairing and filling of the ventricular assist device, to partially support the right heart during the initial wean from cardiopulmonary bypass, and to avoid occasional overdistention of the right heart during early high left ventricular assist device flow.
OBJECTIVE: The authors present their experience with patients having undergone orthotopic heart transplantation (OHT) in whom surgical conditions subsequently developed that required operative intervention. The incidence, morbidity, and mortality of these procedures are reported. SUMMARY BACKGROUND DATA: Several studies have evaluated the management options of biliary tract disease after OHT. Multiple reports of patients having undergone OHT who subsequently underwent peripheral vascular reconstructions, plastic reconstructive, and thoracic procedures also have been published. METHODS: A chart review of 349 patients who underwent OHT between 1985 and 1996 was conducted to identify surgical procedures that were required in the post-transplant period. Their outcomes are reported. RESULTS: Of 349 patients who underwent OHT, conditions requiring 94 surgical procedures developed in 54 patients (15%). Biliary tract disease developed in 17 patients (5%) who required cholecystectomy, 2 of the 5 patients with acute cholecystitis died. Eight patients (2%) underwent orthopedic procedures with no operative mortality. Flap advancements for sternal wound infections were performed in five patients and four deaths occurred. Seventeen thoracic procedures were performed in 11 patients with an overall mortality of 45%. Twenty-one vascular procedures were performed on 17 patients with 1 delayed death due to a malignancy. Seven patients underwent procedures of the colon and rectum with no mortality. Seven patients underwent repair of inguinal or incisional hernias with no mortality. Various infections occurred with one resultant death after operative intervention. Six procedures were performed for diseases of the small intestine with no resultant mortalities. CONCLUSIONS: Patients having undergone OHT and chronic immunosuppression are at increased risk of having complications develop from infection. Acute cholecystitis and sternal wound infection caused an inordinate risk of complications and death. Malignancies developed in four patients who required surgical intervention. A heightened awareness of coexisting peripheral vascular disease in patients transplanted for ischemic cardiomyopathy should exist. Close screening before surgery and surveillance after surgery to identify risk factors for infection and vascular disease and to screen for malignancies are essential.
The use of transgenic cells transplanted in syngeneic rodents has shown modest success, but allogeneic and xenogeneic transplants have not been uniformly successful. To assess the feasibility of xenogeneic and allogeneic myoblast transplantation, we subjected seven adult swine to transplantation of murine atrial tumor cells (xenogeneic), neonatal porcine myocytes (allogeneic), and human fetal cardiomyocytes into the left ventricular wall. After general anesthesia, isolated cells were injected along the anterior and posterior walls of the porcine left ventricle. All the animals were immuno-suppressed and observed for 1 month after injection, at which time they were killed and analyzed. This report will present results primarily concerned with the success of human cell transfers. In all injected sites examined, the transplanted cells thrived within the host myocardium with no significant rejection. Transplant cells formed close associations with host myocytes that resembled nascent intercalated disks on electron microscopy. These cells also contained myofibrils and other cell architecture resembling the transplanted cell lines. Additionally, these cells appeared to produce an angiogenic influence resulting in the proliferation of the surrounding microvasculature. We believe that these findings indicate successful xenogeneic and allogeneic myoblast cell transplantation in a large animal model. These experiments set the stage for future studies to assess the ability of these cells to form a syncytium, contract, and potentially repair failed myocardium.
Lung transplantation is a successful alternative treatment for a variety of end-stage lung diseases. The first 20 lung transplants performed in Louisiana between November 1990 and July 1994 are reported from Ochsner Foundation Hospital. Transplant procedures included 1 heart-lung, 11 bilateral sequential lung, and 8 single-lung transplants in 8 males and 11 females (1 retransplantation). The average age was 38 years (range 7-60), and the median waiting time was 34.5 days (range 1-329). Indications for transplant included emphysema, pulmonary fibrosis, pulmonary hypertension, cystic fibrosis, bronchiectasis, and bronchiolitis obliterans. Overall 1-year and 3-year survival were 65.0% and 58.5%, respectively. Infection was the major cause of morbidity and mortality. Rejection episodes were observed but treated successfully in all 20 patients. Lung transplantation has proved to be a successful treatment for a variety of severely limiting and terminal pulmonary conditions for patients in our state.
Between April 1992 and April 1994, 185 patients were waiting for a cardiac transplant at our institution. Transplantation was performed in 118 of these patients. Twenty-six patients (14%) died while awaiting a donor heart: 13 of these were in the intensive care unit on multiple inotropic medications, mechanical support, or both; another 13 were either in the hospital on a single inotropic medication or at home with or without inotropic support. The remaining 41 patients were still awaiting transplantation at the end of the study period. During the same interval, 20 comparably ill patients who were referred to our institution for transplantation were considered for high-risk conventional surgical procedures. These patients underwent clinical evaluation to determine whether they had viable muscle that was salvageable and electrophysiologic status that was alterable. On this basis, these 20 patients underwent a variety of combined high-risk procedures. Two patients died; the operative mortality was 5% and the cumulative mortality was 10%. We conclude that these initial results support our original impression that mortality rates are higher in patients waiting for cardiac donation than in patients undergoing high-risk surgical procedures. Therefore, we will continue to investigate high-risk conventional surgery as an alternative to cardiac transplantation.
Although the atrioventricular valve and its attachments can sometimes obscure the superior margin of a ventricular septal defect, concern for valvular competence has made surgeons hesitant to take down the atrioventricular valve. Over a 10-year period, the right atrioventricular valve was taken down to improve exposure for ventricular septal defect repair in 40 patients at our institution, and follow-up echocardiographic studies to determine the degree of valvular regurgitation were available in 32. On the basis of the area of the color flow jet, valvular regurgitation was graded as none in 22 and trivial in 10. Heart block did not develop in any patient, and there were no deaths. Takedown and resuspension of the atrioventricular valve is a safe and effective technique that improves exposure for ventricular septal defect repair and does not adversely affect valve competence.
Due to the high incidence of death while awaiting cardiac transplantation today, most major transplant centers have adopted the use of left ventricular assist devices in order to stave off the complications of end-stage heart failure and allow patients to maintain a good physiologic state going into heart transplantation. These devices are safe and may one day prove to be a substitute for the short supply of donor organs.
The improved outcome following cardiac transplantation has produced changes in the traditional criteria for potential candidates. We have analyzed these changes and the clinical aspects involved in the selection process, which are of critical importance to assure an excellent result of cardiac transplantation in patients with advanced heart failure.
Cardiac allograft rejection represents a major cause of morbidity and mortality in transplanted patients. Noninvasive markers of rejection have been sought, though transvenous endomyocardial biopsy remains the "gold standard" for the diagnosis of rejection. Sixty-one signal-averaged electrocardiograms (five in patients with rejection and 56 in patients without rejection) were obtained on 41 patients and prospectively analyzed in frequency domain via fast Fourier transform (FFT). Patients with acute allograft rejection demonstrate a significant increase in the high-frequency components of the QRS complex upon FFT analysis (QRS area ratio 203 +/- 57 vs. 66 +/- 10, P = 0.0007) compared with patients without rejection. Thus, frequency domain analysis may be a useful noninvasive marker of acute cardiac allograft rejection.
Congenital long-segment intrathoracic tracheal stenosis (CTS) is a rare life-threatening obstruction in infancy and childhood. From July 1983 to March 1988 six infants aged 14 days to 14 months with CTS were identified. Symptoms ranged from recurrent stridor and wheezing to severe respiratory compromise and hypercarbia. Routine chest x-rays were not diagnostic. Definitive diagnosis was made by bronchoscopy, which showed complete tracheal rings in all patients with severely compromised tracheobronchial lumens. In three patients, pericardium was successfully used for anterior tracheoplasty with one early death due to fulminant sepsis in an infant with undiagnosed sickle cell disease. The other two died late, at 3 and 9 months from problems unrelated to the repair. In three patients a rib graft was used for repair; in one, tracheoplasty was required after earlier repair of tetralogy of Fallot. All are late survivors with no postoperative symptoms. After recognition of CTS, prompt surgery is warranted to avoid the late complications of tracheostomy for long-term ventilatory support. Rigid repair with rib cartilage is preferable to use of pericardium. Proper rib harvesting with intact perichondrium, intraoperative bronchoscopy, oxygenation by cardiopulmonary bypass, and meticulous graft alignment are necessary for successful postoperative outcome.
Advances in the surgical management of ventricular tachyarrhythmias have been dramatic in recent years. Seriously ill patients, with or without ventricular aneurysms, who have medically refractory ventricular tachyarrhythmias may be candidates for intraoperative electrophysiologic mapping with surgical excision and/or cryoblation of the foci of their arrhythmias. In properly selected patients current techniques may offer success rates in excess of 90%. We report two cases of patients who have undergone such a procedure with excellent results. Indications for and results of surgical management are discussed.
The internal mammary artery is used with increasing frequency for myocardial revascularization. However, preoperative coronary angiography does not always provide adequate visualization of subclavian arteries. If a proximal subclavian artery stenosis exists or develops in a patient who has myocardial revascularization with the internal mammary artery, graft malfunction can occur resulting in myocardial ischemia. We have identified four cases of internal mammary artery graft malfunction at our own institution and identified an additional 12 cases from the literature. These 16 cases are analyzed for age, sex, time of onset of symptoms, clinical findings, method of revascularization, and long-term follow-up. Sixty-three percent of the patients were men, and the mean age was 52.9 +/- 9.0 years. Onset of symptoms occurred after a mean interval of 25.1 months from the time of myocardial revascularization. Three patients had asymptomatic reversal of flow in the internal mammary artery as diagnosed by coronary arteriography during routine follow-up examination before 1980. One death after internal mammary artery-coronary bypass grafting was related to immediate malfunction. In the remaining 12 patients with symptomatic malfunction, all but one were treated by placement of a carotid-subclavian bypass graft with no mortality. Relief of myocardial ischemia was complete in 93% of the patients with a mean follow-up of 29.3 months. Carotid-subclavian bypass grafting appears to be the treatment of choice for the usual management of internal mammary artery graft dysfunction. Careful preoperative evaluation and postoperative follow-up of the subclavian arteries, even by simple comparison of bilateral arm blood pressure should help reduce the incidence of this syndrome.