Biomedical subjects
Publications and source records attributed to Igor D Gregoric.
The long-term effects of axial-flow mechanical circulatory support in humans are unclear. We report 3 cases of chronic gastrointestinal bleeding after implantation of a Jarvik 2000 axial-flow left ventricular assist device. The bleeding was refractory to aggressive management and in 2 cases resolved only after orthotopic cardiac transplantation.
One of the complications that can occur with continuous, axial-flow left ventricular assist devices (LVADs) is thrombosis within the left ventricle, adjacent to the device's inflow conduit, which may cause inflow obstruction and recurrent heart failure. We describe 2 cases in which we used a catheter to continuously infuse recombinant tissue plasminogen activator (tPA) into the left ventricle until signs of successful thrombolysis was achieved. By monitoring the result and administering only as much tPA as necessary to achieve thrombolysis, we were able to successfully lyse the obstructing thrombus with a minimal dose of tPA without causing any significant bleeding problems. This technique may be useful for managing this potentially serious complication while minimizing the risk of treatment.
Cardiac alpha one adrenoreceptors (alpha(1)AR) are known to mediate positive inotropism in human ventricular myocardium. In the early stages of heart failure, ventricular contractility is maintained by adrenergic stimulation, rennin-angiotensin activation, and other neurohormonal and cytokine system responses. As the disease progresses, however, these compensatory mechanisms cease to provide benefit; ventricular dilation and fibrosis occur and cardiac function deteriorates. When ventricular contractility becomes severely depressed and is no longer responsive to inotropic support, insertion of a left ventricular assist device (LVAD) may allow the left ventricle to rest, remodel, and recover some contractile function. Our previous work has demonstrated that the myocardium has the capacity to repair itself during a period of unloading, after which some patients are able to resume a normal lifestyle and no longer need a cardiac transplant.
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BACKGROUND: Several studies have shown that percutaneous dilational tracheostomy (PDT) is safe and cost-effective for patients recovering from surgery that requires a median sternotomy. We report our experience with PDT in patients receiving mechanical cardiac assistance. METHODS: We reviewed the medical records of all patients who underwent ventricular assist device implantation at our institution between July 2000 and July 2003, and who subsequently required long-term ventilatory support during the same hospital admission. Data obtained from the records included demographic and biometric information, primary diagnosis, early (< or =30days) and late (>30days) complications, date and cause of death, type of anti-coagulation used at the time of tracheostomy, and various coagulation measures. RESULTS: Thirty-one consecutive patients (29 men, 2 women; mean age, 56 years) had PDT after ventricular assist device implantation. Four minor complications occurred among 3 of the patients (10%), including 3 early complications (2 peristomal oozing and 1 peristomal cellulitis) and 1 late complication (recurrent peristomal cellulitis), none of which affected long-term outcome. No major adverse events, long-term complications, or deaths resulted from the PDT procedure. CONCLUSIONS: PDT is feasible for patients with mechanical support devices who require long-term ventilatory support. Although some of these patients are coagulopathic, our results indicate that PDT is safe and effective in this challenging patient population.
OBJECTIVE: Although the surgical management of brachiocephalic disease is well established, evolving endovascular techniques present new options for treatment. We explored the potential benefits and drawbacks of these interventions in terms of outcome. METHODS: From 1966 to 2004, 391 consecutive patients (43.7% male; mean age, 61.9 years) with single-vessel brachiocephalic disease were treated with either operative bypass (group A; n = 229) or percutaneous transluminal angioplasty and stenting (group B; n = 162). RESULTS: All patients were asymptomatic after surgery or endovascular intervention. Group A and group B had similar operative mortality (0.9% vs 0.6%) and stroke (1.3% vs 0%) rates. However, 5 years after the procedure, group A had significantly better freedom from graft or intervention failure (92.7% +/- 2.1%) than did group B (83.9% +/- 3.7%; P = .03, Kaplan-Meier analysis; P = .001, Cox regression analysis). At 10 years, group A had the following rates of actuarial freedom from specific events: death, 73.7% +/- 4.6%; myocardial infarction, 84.2% +/- 3.6%; stroke, 91.4% +/- 3.4%; graft failure, 88.1% +/- 3.3%; coronary revascularization, 69.8% +/- 5.1%; and other vascular operation, 70.7% +/- 4.6%. Endovascular intervention involved less initial cost (mean savings, $8787 per procedure), was less invasive, and did not necessitate general anesthesia. On satisfaction questionnaires, 96.5% of patients receiving an endovascular intervention and 95.1% of patients receiving operative bypass for single-vessel brachiocephalic disease subjectively rated their treatment as "good" or "very good." CONCLUSIONS: Operative bypass and endovascular intervention for single-vessel brachiocephalic disease are both associated with acceptably low operative morbidity and mortality. Operative bypass produces significantly better mid-term freedom from graft or intervention failure than endovascular intervention and produces excellent long-term freedom from failure. Endovascular intervention offers tangible benefits regarding cost, level of invasiveness, and subjective patient satisfaction. Undetermined are the differences between the procedures regarding long-term durability, patterns of failure, efficacy as an adjunct to coronary artery bypass grafting, need for anticoagulation, efficacy as treatment for complex (multivessel) disease, and long-term cost.
OBJECTIVES: Complex brachiocephalic disease involves multiple vessels and is frequently associated with multisystem atherosclerosis. We reviewed surgical outcome and examined the impact of this problem on decision making regarding operative staging, technique, and choice of conduit. METHODS: Between 1966 and 2000, 157 consecutive patients (mean age, 54.0 years; 48.4% male) with innominate artery or multivessel brachiocephalic disease underwent operative reconstruction using either a transthoracic approach (group A, n = 113) or a less invasive, extrathoracic approach (group B, n = 44). Reconstruction required multiple distal anastomoses in 70 patients (44.6%), concomitant coronary artery bypass grafting (CABG) in 37 patients (23.6%), and concomitant carotid endarterectomy (CEA) in 26 patients (16.6%). RESULTS: No significant differences were found between group A and group B when operative mortality (2.7% vs 2.3%) and stroke rates (2.7% vs 6.8%) were analyzed. However, 10 years after surgery, freedom from graft failure was significantly better in group A (94.4% +/- 4.4%) than in group B (60.3% +/- 13.4%) ( P = .002). Freedom from graft failure was adversely affected by nonaortic inflow ( P = .002) and axillo-axillary cervical grafts ( P = .0001). Mortality and stroke rates for subgroups having multiple distal anastomoses (2.9%, 2/70 and 4.3%, 3/70), concomitant CABG (5.4%, 2/37 and 0, 0/37), and concomitant CEA (3.8%, 1/26 and 3.8%, 1/26) were similar to those of other patients. For the entire patient group, 10-year rates of actuarial freedom from specific events were death, 68.8% +/- 6.0%; myocardial infarction, 86.7% +/- 4.5%; stroke, 87.0% +/- 4.4%; coronary revascularization, 88.0% +/- 3.6%, and other vascular operation, 79.9% +/- 4.4%. CONCLUSIONS: Transthoracic arch reconstruction for complex brachiocephalic disease can be done with acceptably low morbidity and mortality similar to those of a less invasive, extrathoracic approach. Furthermore, the transthoracic approach is associated with significantly better long-term freedom from graft failure, possibly because it preserves aortic inflow to the great vessels. Nonetheless, the high frequency of late events in this relatively young patient population reflects the presence of multisystem atherosclerosis and suggests the need for close follow-up and lifestyle modification.
Critically ill heart failure patients undergoing left ventricular assist device implantation have alterations in their coagulation profiles; as a result, hemorrhagic complications during the postoperative period are the most common and serious problems during device support of these patients. The use of aprotinin therapy is generally accepted for reducing bleeding after coronary artery bypass grafting procedures, heart transplantation, and insertion of a left ventricular assist device. We describe the case of a patient who had a suprasystemic increase in pulmonary artery pressure, caused by thromboembolic occlusion of the pulmonary arterioles after urgent implantation of a left ventricular assist device. The complications developed after the patient was weaned from cardiopulmonary bypass and heparinization was reversed with protamine. Although the thrombosis was successfully reversed with intraoperative administration of tissue plasminogen activator directly to the pulmonary artery, the patient died of massive hemorrhage 6 hours later. To our knowledge, the direct application of tissue plasminogen activator into the pulmonary artery in such a catastrophic situation has not been used elsewhere.
Reoperative aortic surgery is a therapeutic challenge. We examine a case of reoperative aortic surgery involving a pseudoaneurysm that occurred after surgical treatment of an abdominal aneurysm. A systematic approach to diagnosis, followed by treatment tailored to diagnostic findings, can minimize morbidity.
Axial-flow ventricular assist devices (VADs) can be implanted either through a left thoracotomy with outflow-graft anastomosis to the descending thoracic aorta or through a midline sternotomy with anastomosis to the ascending aorta. Each method has advantages and disadvantages. Because these VADs produce nonpulsatile flow, their hemodynamic characteristics differ from those of pulsatile devices. These differences may have important clinical consequences, particularly in relation to the outflow-graft configuration. We describe a computer-generated flow model that we created to illustrate the flow dynamics and possible clinical consequences of each method. The simulations indicate that the location of the anastomosis has important qualitative effects on flow in the ascending aorta and aortic arch. At high VAD outputs (> or =75%), native cardiac output cannot supply the carotid and subclavian arteries. With a descending aortic anastomosis, net backward flow occurs in the descending aorta to supply these branches. Consequently, the aortic arch has a region with almost no net flow, where fluid particles stagnate over many cardiac cycles, possibly causing thrombogenesis. With an ascending aortic anastomosis, the arch has no stagnant region, although flow turbulence still occurs. When the aortic valve remains closed, so that the total output occurs through the VAD, the aortic root has a region of nearly stagnant flow. With an ascending aortic anastomosis, a small degree of recirculatory flow may prevent complete stagnation at the aortic root. With the descending aortic anastomosis, however, no recirculation occurs. These results help delineate the complex flow dynamics and the advantages and drawbacks of each technique.
As the prevalence and incidence of ischemic heart disease continue to increase, so does interest in ischemic heart failure management. Limitations of current therapies have led to research aimed at regenerating and repairing ischemically damaged myocardium through stem-cell therapy. Cell types being evaluated include embryonic stem cells, fetal and neonatal cardiomyocytes, skeletal myoblasts, bone marrow stem cells, peripheral blood CD34+ cells, endothelial progenitor cells, cardiac progenitor cells, and fibroblasts. Preclinical animal studies and promising early results of clinical trials now under way suggest that stem-cell therapy may soon become an important new tool in heart failure management.
We report the case of a 14-year-old boy who developed ischemic contracture of the heart after open heart surgery to correct complex congenital heart disease. Because he had no cardiac function, an extracorporeal, continuous-flow device was used to support him until he was transferred to our institution. Shortly after his arrival, an implantable, long-term left ventricular assist device was implanted. The univentricular pump provided total cardiac support for this critically ill patient. After normalization of end-organ function, the patient underwent successful orthotopic cardiac transplantation.
Historically, open surgical repair of thoracoabdominal aortic aneurysms has been associated with high morbidity and mortality rates. Furthermore, endovascular exclusion alone can restrict blood flow to visceral arteries. We report a case of thoracoabdominal aortic aneurysm that was repaired using a hybrid approach: surgery followed by an endovascular procedure. A 53-year-old woman was admitted to our hospital for endovascular exclusion of a thoracoabdominal aortic aneurysm that included the superior mesenteric artery and the celiac artery. Aorto-mesenteric and aorto-celiac artery bypass grafting was performed to create a landing zone for subsequent endovascular exclusion of the aneurysm, which was completed successfully 6 weeks after the bypass procedure. For thoracoabdominal aortic aneurysms that extend beyond the superior mesenteric artery and the celiac or renal arteries, a hybrid approach, consisting of limited surgical treatment followed by endovascular exclusion of the aneurysm, may yield optimal results in selected patients with serious preoperative comorbidities.
We describe a case of subacute left ventricular free wall rupture during acute myocardial infarction in a 68-year-old man. The diagnosis was confirmed by echocardiography. The patient was supported by an intra-aortic balloon pump until the ruptured wall could be successfully repaired by suturing and gluing a pericardial patch over the defect and bypassing the left anterior descending coronary artery with a vein graft. This case demonstrates that left ventricular free wall rupture is not always fatal and that early diagnosis and institution of intra-aortic balloon pump support in such patients can allow successful bridging to definitive emergency surgical therapy.
A 57-year-old man, who had received a heart transplant 14 years earlier, underwent coronary artery bypass grafting and transmyocardial laser revascularization for left main, left anterior descending, and circumflex coronary artery disease. The procedures were performed through a left thoracotomy incision without cardiopulmonary bypass. Because the patient was of the Jehovah's Witness faith, no blood or blood products were transfused.
During heart transplantation, the atrial septum is most often used to reconstruct the right atrial reservoir. We report the case of a patient with corrected D-transposition of the great arteries who underwent successful cardiac transplantation despite the lack of an atrial septum. We then used the donor heart's atrial septum for the roof of the left atrium and used the recipient's left atrium for the back wall of the left atrium. The outcome was a more anatomically positioned transplanted heart, which avoided the duplication of the right and left atria that occurs in conventional orthotopic transplantation and that often leads to left-lower-lobe atelectasis and tricuspid regurgitation. This method of orthotopic transplantation should be considered for, but not limited to, the growing number of adults with congenital heart disease who require heart transplantation.
Congenitally corrected transposition of the great arteries (ccTGA) is a rare anomaly characterized by atrioventricular and ventriculo-arterial discordance and several other malformations that eventually lead to heart failure. We describe the case of a 53-year-old woman with ccTGA and aortic insufficiency who was a candidate for heart transplantation due to end-stage congestive heart failure. Her condition deteriorated before a suitable donor heart could be found; therefore, we placed a left ventricular assist device in the right (systemic) ventricle. Concomitantly, we removed the aortic (systemic) valve, closed the aortic annulus with a bovine pericardial patch, and repaired the mitral valve. The patient recovered uneventfully and was discharged from the hospital 2 months postoperatively. She underwent cardiac transplantation approximately 6 months later and continued to do well after 18 months.
We present an illustrative case of postpartum ovarian vein thrombosis and describe its clinical presentation, differential diagnosis, and management. This pathologic process may produce clinical complications or a catastrophic outcome. These adverse events may be avoided if an expeditious diagnosis is made and appropriate treatment is instituted. This mandates a high index of suspicion, the ability to rule out the presence of other processes that may produce similar symptoms in the postpartum patient, and the appropriate triage of specific patients to either medical or surgical management.