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Biomedical subjects

Bansi Koul

Publications and source records attributed to Bansi Koul.

6 recordsLinked to original sources

A modified Ross operation to prevent pulmonary autograft dilatation.

A modification in Ross operation is described in which the free-standing pulmonary autograft root is suspended in a Dacron prosthetic vascular jacket with a view to prevent dilatation of the neo-aortic root. In a group of 13 patients operated consecutively using this technique, there was no significant increase in the diameters of the neo-aortic root after a mean 16-month follow-up. Aortic valve function remained also satisfactory.

Adult↗

Mechanical reliability of the Jarvik 2000 Heart.

BACKGROUND: Device failure is a limitation of permanent mechanical circulatory support. We studied the mechanical reliability of the Jarvik 2000 Heart, an axial flow pump with ceramic bearings designed to provide more than 10 years' durability. METHODS: The Jarvik 2000 Heart was implanted in 102 patients between April 2000 and December 2004. Eighty-three pumps with an abdominal driveline were implanted as a bridge-to-transplantation, and 19 with postauricular power supply as lifetime therapy. Eighteen pumps were recovered intact after clinical use and run continuously on the bench to further assess durability. RESULTS: No implantable component failure occurred either in patients or during bench testing. The cumulative pump run-time was 110 years: 59 years overall in vivo and 51 years in vitro. The mean support time for bridge-to-transplant recipients was 159 days, and for discharged lifetime-therapy recipients 551 days. Six recipients were supported moer than 2 years, with the longest ongoing approaching 5 years. External cables caused three system failures, with a 95% freedom from system failure at 4 years. Device malfunctions, related to external cables (9) and lack of a backup battery (1), caused no adverse consequences. Before introduction of noncorrosive, gold-plated stainless steel connectors, corrosion was observed on three connectors to the retroauricular power supply. CONCLUSIONS: The Jarvik 2000 Heart has had no implantable component failure. Meaningful durability data and failure mode can only be established by real-time testing in patients. The reliability and dependability of this device, in addition to the exchangeability of external components, give promise for long-term circulatory support in critically ill heart failure patients.

Equipment Failure Analysis↗

Selective mediastinal tamponade to control coagulopathic bleeding.

End-stage congestive heart failure in combination with major cardiac surgery may cause severe postoperative bleeding due to coagulopathy. Bleeding diathesis can be very difficult to control despite careful surgical hemostasis and aggressive medical treatment. We describe a technique that involves the use of negative pressure in the mediastinum to control severe postoperative bleeding after cardiac surgery.

Blood Coagulation Disorders↗

Risk factor analysis of Swedish Left Ventricular Assist Device (LVAD) patients.

BACKGROUND: The use of left ventricular assist devices (LVADs) is established as a bridge to heart transplantation. METHODS: All Swedish patients on the waiting list for heart transplantation, treated with LVAD since 1993 were retrospectively collected into a database and analyzed in regards to risk factors for mortality and morbidity. RESULTS: Fifty-nine patients (46 men) with a median age of 49 years (range, 14 to 69 years), Higgins score median of 9 (range, 3 to 15), EuroScore median of 10 (range, 5 to 17) were investigated. Dominating diagnoses were dilated cardiomyopathy in 61% (n = 36) and ischemic cardiomyopathy in 18.6% (n = 11). The patients were supported with LVAD for a median time of 99.5 days (range, 1 to 873 days). Forty-five (76%) patients received transplants, and 3 (5.1%) patients were weaned from the device. Eleven patients (18.6%) died during LVAD treatment. Risk factor analysis for mortality before heart transplantation showed significance for a high total amount of autologous blood transfusions (p < 0.001), days on mechanical ventilation postoperatively (p < 0.001), prolonged postoperative intensive care unit stay (p = 0.007), and high central venous pressure 24 hours postoperatively and at the final measurement (p = 0.03 and 0.01, respectively). Mortality with LVAD treatment was 18.6% (n = 11). High C-reactive protein (p = 0.001), low mean arterial pressure (p = 0.03), and high cardiac index (p = 0.03) preoperatively were risk factors for development of right ventricular failure during LVAD treatment. CONCLUSIONS: The Swedish experience with LVAD as a bridge to heart transplantation was retrospectively collected into a database. This included data from transplant and nontransplant centers. Figures of mortality and morbidity in the database were comparable to international experience. Specific risk factors were difficult to define retrospectively as a result of different protocols for follow-up among participating centers.

Adolescent↗

Ross operation for bicuspid aortic valve disease in adults: is it a valid surgical option?

OBJECTIVE: The validity of the Ross operation as freestanding root replacement in adult patients with bicuspid aortic valve disease has lately been questioned. We have analyzed retrospectively our results in 23 adult patients (19 males) operated for bicuspid aortic valve disease ad modum "Ross" employing a freestanding root replacement technique. DESIGN: In 9 patients the dominant aortic valve lesion was stenotic (aortic stenosis group) and in the remaining 14 patients it was aortic insufficiency (aortic insufficiency group). The fate of the pulmonary autograft in the two groups was studied. The intraoperatively measured aortic and pulmonary annuli diameters from the two groups were compared with those from a population of normal looking aortic and pulmonary valves matched for body surface area. RESULTS: The aortic insufficiency group needed significant reduction of the aortic annulus diameter to conform to the size of the pulmonary autograft. The pulmonary autograft annuli in this group were significantly larger in diameter than the ones in the aortic stenosis group. The mean pulmonary annulus diameter in the aortic stenosis group was, on the other hand, significantly smaller when compared with that in the normal matched population. After a mean follow-up period of about 19 months, the aortic insufficiency group showed significant dilatation of the neo-aortic sinuses. Between the two groups, the remaining echocardiographic variables remained either stable or improved at follow-up. CONCLUSION: Pre-existing larger diameters of the aortic and pulmonary annuli in the aortic insufficiency group combined with the significantly increased left ventricular end-diastolic diameters, may predispose these patients to significant dilatation of the unsupported aortic sinuses after a Ross operation. This dilatation does not, however, lead to increase in the autograft valve insufficiency at short-term follow-up if the aortic annulus and the distal ascending aorta are tailored to the size of the pulmonary autograft. Ross operation, employing freestanding aortic root replacement technique, may therefore be recommended in adult patients with bicuspid aortic valve disease with excellent short-term results.

Adolescent↗