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Biomedical subjects

A Ruchan Akar

Publications and source records attributed to A Ruchan Akar.

5 recordsLinked to original sources

Regenerative medicine for cardiovascular disorders-new milestones: adult stem cells.

Cardiovascular disorders are the leading causes of mortality and morbidity in the developed world. Cell-based modalities have received considerable scientific attention over the last decade for their potential use in this clinical arena. This review was intended as a brief overview on the subject of therapeutic potential of adult stem cells in cardiovascular medicine with basic science findings and the current status of clinical applications. The historical perspective and basic concepts are reviewed and a description of current applications and potential adverse effects in cardiovascular medicine is given. Future improvements on cell-based therapies will likely provide remarkable improvement in survival and quality of life for millions of patients with cardiovascular disorders.

Adult↗

Primary pericardial mesothelioma.

Pericardial mesothelioma is a rare cancer for which treatment options are limited. Operative intervention in pericardial mesothelioma is primarily for effusion control, for cytoreduction before multimodal therapy, or to deliver and monitor innovative intrapericardial therapies. Misdiagnosis is common. Early detection of the disease is the only hope for survival. Echocardiography, pathologic examination of pericardial fluid and pericardial biopsy, Gallium-67 scintigraph, Ber-EP4 antibody, and immunohistochemical procedures can be used. Magnetic resonance imaging is emerging as the best modality for demonstrating the nature and extent of the constrictive process, and the infiltration to the cardiac wall and great vessels. Failure of surgical techniques is usually associated with mesothelioma with entrapped heart, a large solid tumor mass, and a long history of pericardial effusion. If the tumor is localized, resection is the only hope for this rare, but lethal, entity. No single treatment modality is efficient by itself. The exact role of intracavitary chemotherapy or irradiation remains to be defined. Preliminary clinical application of photodynamic therapy and attempts at inhibiting the effects of growth factors, such as vascular endothelial growth factor and platelet-derived growth factor, and vaccine treatments are being explored. Adenoviral molecular chemotherapy recently completed phase I testing. Clinical trials for pleural mesothelioma remain important as clinicians seek to improve the outcome for patients with pericardial mesothelioma. Early diagnosis and multidisciplinary patient care is essential for improved surgical outcome. In the future, combined therapeutic strategies involving radical surgery, radiotherapy, adjuvant chemotherapy, and immunomodulation may have a role in the treatment of pericardial mesotheliomas.

Heart Neoplasms↗

Use of stentless xenografts in the aortic position: determinants of early and late outcome.

BACKGROUND: Whether to perform a stentless aortic valve replacement (AVR) is not well established. Our aim was to determine the outcome after AVR with stentless xenograft valves. METHODS: Between 1996 and 2001, a total of 404 patients (mean age 70.4 years) underwent a stentless AVR by one surgeon in our unit. Concomitant procedures were performed in 132 patients (33%). Twenty patients (6.4%) had undergone previous AVR. Eleven types of stentless xenograft valves were implanted: Medtronic Freestyle in 221 patients (55%), Shelhigh in 55 (14%), Shelhigh composite conduit in 33 (8%), Sorin in 26 (6%), Cryolife O'Brien in 25 (6%), Aortech-Elan in 17 (4%), Edwards Prima in 14 (4%), Toronto SPV in 7 (2%), and other valves in 6 (1%). A subcoronary implantation technique was used in 302 cases (76%), complete root replacement in 62 (15%), and a modified Bentall-De Bono procedure in 33 (8%). Mean follow-up was 19.4 months (range, 1.2 to 60.6 months). RESULTS: Overall hospital mortality was 4.2%. This was 2.4% for isolated AVR, 3.6% for AVR and coronary artery bypass grafting, 5.5% for replacement of two or more valves, and 12% for the modified Bentall procedure. On multiple logistic regression redo cardiac operation (p = 0.0006), cardiogenic shock (p = 0.001), left ventricular ejection fraction less than 0.30 (p = 0.01), modified Bentall procedure (p = 0.03), and endocarditis (p = 0.04) were predictors of in-hospital death. Five-year freedom from thromboembolism, hemorrhage, prosthetic endocarditis, structural valve deterioration, and reoperation was 97%, 99%, 99%, 98%, and 96%, respectively. Kaplan-Meier survival at 5 years was 88%. On Cox regression, cardiogenic shock (p = 0.001) and older age (p = 0.03) were adverse predictors of survival. At echocardiographic examination within 6 months from the operation, mean aortic valve gradients were 15 +/- 6 mm Hg, 12.8 +/- 3 mm Hg, 10.8 +/- 4 mm Hg, 9.3 +/- 3 mm Hg, 9.1 +/- 4 mm Hg, and 8.2 +/- 3 mm Hg for valve sizes of 19, 21, 23, 25, 27, and 29 mm, respectively. CONCLUSIONS: The availability of several stentless valve designs facilitates the surgical treatment of diverse aortic valve or root diseases with encouraging early and mid-term results. Patients requiring concomitant procedures may also benefit from the excellent hemodynamic characteristics of a stentless valve. We consider stentless AVR the treatment of choice for patients older than 60 years and those having small aortic roots.

Adult↗

Mitral valve relpair and revascularization for ischemic mitral regurgitation: predictors of operative mortality and survival.

BACKGROUND AND AIMS OF THE STUDY: Surgery for ischemic mitral regurgitation (IMR) is required in 4-5% of patients subjected to coronary artery surgery, and may be challenging. The study aim was to determine outcome following mitral valve repair and myocardial revascularization for moderate-to-severe IMR. METHODS: A total of 102 patients (mean age 68+/-7 years) underwent mitral valve repair for IMR between 1998 and 2001 at the authors' unit. Among patients, 28 had acute and 74 chronic mitral regurgitation (MR). Valve repair was achieved with an annuloplasty ring in all 102 patients, while 99 underwent concomitant myocardial revascularization. Preoperatively, 69 patients had MR grade III-IV, 62 had CCS angina class III-IV, 59 were in NYHA class II-IV, 81 had impaired left ventricular function, and 10 were in cardiogenic shock. Follow up was 100% complete (mean 14+/-7 months; range: 0-38 months). RESULTS: Overall operative mortality was 8.8% (n = 9) (17.8% for acute IMR, 5.4% for chronic, p = 0.048). On multiple logistic regression analysis, cardiogenic shock (p = 0.028) was the only significant risk factor for operative death. There were 11 late deaths. Kaplan-Meier survival at one and three years was 82+/-4% and 79+/-4%, respectively. On Cox proportional hazards regression model, preoperative left ventricular end-systolic diameter (LVESD) >4.5 cm (p = 0.01) and NYHA class III-IV (p = 0.02) were independent adverse predictors of survival. Three patients required reoperation. Kaplan-Meier three-year freedom from reoperation was 97+/-2%. CONCLUSION: Surgery for IMR carries a considerable, but acceptable, operative risk and provides satisfactory freedom from reoperation and mid-term survival. Cardiogenic shock before surgery is the major determinant of an unfavorable in-hospital outcome. LVESD >4.5 cm and poor preoperative NYHA status limit the probability of late survival. The study results support early surgical intervention for IMR, before ventricular dilatation occurs.

Aged↗