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Biomedical subjects

V Falk

Publications and source records attributed to V Falk.

At least 91 records · Page 5Linked to original sources
PubMed1997

Morphometric study of the right gastroepiploic and inferior epigastric arteries.

BACKGROUND: Based on earlier observations that the thickness of the intima and structure of the media may have an impact on the long-term patency of arterial conduits and the lack of detailed histologic studies of the right gastroepiploic and inferior epigastric arteries, we subjected both vessels to morphometric analysis with emphasis on their suitability as conduits in myocardial revascularization. METHODS: The right gastroepiploic and inferior epigastric arteries were harvested from 28 unselected individuals (mean age, 73.2 years) at autopsy, and the luminal diameter and the width of the intima and media were measured. RESULTS: At all levels of measurement (origin, 10 cm, and 15 cm), the luminal diameter of the inferior epigastric artery was significantly smaller than that of the right gastroepiploic artery (p < 0.05). The right gastroepiploic artery demonstrated only mild intimal hyperplasia. In contrast, the inferior epigastric artery showed substantial intimal hyperplasia within the first 1-cm segment (mean, 134 +/- 131 microns versus 50 +/- 49 microns for the corresponding segment of the right gastroepiploic artery; p = 0.01). Intimal hyperplasia was only mild in the remainder of the inferior epigastric artery. In both vessels, the media was muscular with rare dispersed elastic fibers. The mean thickness of the media ranged from 380 +/- 116 microns proximally to 155 +/- 70 microns distally for the right gastroepiploic artery, and from 316 +/- 86 to 165 +/- 70 microns, respectively, for the inferior epigastric artery. CONCLUSIONS: In myocardial revascularization, use of the right gastroepiploic artery may generally be preferable to use of the inferior epigastric artery. This recommendation is based on the larger luminal diameter of the right gastroepiploic artery as compared with the inferior epigastric artery, the significantly greater intimal hyperplasia in the first segment of the inferior epigastric artery, and the limitation that the inferior epigastric artery can be used only as a free graft. The rate of development of intimal hyperplasia in the right gastroepiploic artery, if used as an in situ coronary artery bypass graft, may be slow, approximating that of the right gastroepiploic artery in its natural environment.

Aged↗
PubMed1997

Thermal coronary angiography for intraoperative testing of coronary patency in congenital heart defects.

Intraoperative thermal coronary angiography was successfully applied in 9 patients who underwent operative correction of congenital heart defects: arterial switch operation for transposition of the great arteries (n = 5), Ross operation for valvar aortic stenosis with regurgitation (n = 3), and aortic implantation of the left coronary artery for anomalous connection of the left coronary artery to the pulmonary artery (n = 1). Intraoperative thermal coronary angiography allows early detection and surgical correction of coronary ostial obstruction.

Coronary Angiography↗
PubMed1997

Instantaneous subaortic outflow obstruction after volume reduction in hearts with univentricular atrioventricular connection and discordant ventriculoarterial connection.

OBJECTIVE: To study the phenomenon of potential subaortic outflow obstruction after surgical volume unloading of the heart in patients with univentricular atrioventricular connection, discordant ventriculoarterial connection, and bulboventricular foramen (BVF)-dependent systemic flow. MATERIAL AND METHODS: Intraoperative transesophageal echocardiography was used in five patients with tricuspid atresia (N = 3) or double-inlet left ventricle (N = 2) with rudimentary right ventricle and BVF who were scheduled to undergo a bidirectional cavopulmonary anastomosis (N = 3) or completion of the Fontan procedure after previous banding of the pulmonary artery (N = 2). The BVF diameter was measured in two orthogonal views, and the area was calculated by using the formula for an ellipse. Left ventricular posterior wall thickness and left ventricular internal diameter were also measured. Intraoperative prerepair and postrepair gradients across the BVF were measured by echocardiography. RESULTS: Volume unloading of the left ventricle resulted in instantaneous contraction of left ventricular size (decrease of median left ventricular internal diameter from 38 to 34 mm and increase of median left ventricular posterior wall thickness from 5 to 7 mm), decrease of median BVF area index (from 1.82 to 1.55 cm2/m2), and development of a median gradient of 60 mm Hg across the BVF. At a mean follow-up of 19.6 months, all patients were clinically well and had no echocardiographic evidence of BVF obstruction. CONCLUSION: In hearts with univentricular atrioventricular connection, discordant ventriculoarterial connection, and BVF-dependent systemic flow, a decrease in ventricular volume is associated with an instantaneous alteration in ventricular geometry, diminution in BVF size, and potential for subaortic outflow obstruction. Intraoperative transesophageal echocardiography is of paramount importance in excluding development of subaortic outflow obstruction in this setting.

Anastomosis, Surgical↗
PubMed1997

Repair of subaortic stenosis in atrioventricular canal with absent or restrictive interventricular communication by patch augmentation of ventricular septum, resuspension of atrioventricular valves, and septal myectomy.

OBJECTIVE: To describe a modification of a surgical technique for relief of subaortic stenosis in patients with atrioventricular canal. MATERIAL AND METHODS: We report an etiology-oriented modified technique of repair of subaortic stenosis after previous repair of atrioventricular canal, without (N = 2) or with (N = 1) a restrictive interventricular communication. RESULTS: In addition to a generous myectomy of the left ventricular septum, the technique consists of complete detachment of the left and right atrioventricular valves from the ventricular crest, patch augmentation of the concavity of the ventricular crest, and attachment of both atrioventricular valves at the superior aspect of the ventricular septal patch; thus, the septal leaflet of the left atrioventricular valve--in particular, its superior component--is lifted away from the elongated left ventricular outflow tract. CONCLUSION: This modification (as opposed to detachment of only the superior component of the septal leaflet of the left atrioventricular valve, as performed in previously proposed techniques) may be a valuable adjunctive technique to relieve subaortic obstruction associated with atrioventricular canal. In addition, this modification allows a secure anchoring of the patch to the right of the ventricular septum and therefore is associated with minimal risk of damaging the conduction tissue and of causing regurgitation of the left atrioventricular valve.

Aortic Valve Stenosis↗
PubMed1997

Stentless valve replacement in the small aortic root.

Despite the variety of different artificial heart valves available, no ideal prosthesis for the small aortic root has yet been identified. The aim of this study was to evaluate the haemodynamic performance and clinical outcome after stentless aortic valve replacement. A total of 70 patients with a small aortic root underwent Toronto (n = 61) or Freestyle (n = 9) stentless aortic valve replacement. All but three patients had aortic stenosis. Mean (s.d.) age at operation was 71.2(7.9) years. The mean annular diameter was 21.4(1.2) mm. Using controlled oversizing adjusting valve size to the sinotubular junction diameter, a 23-mm prosthesis was implanted in 23 patients and a 25-mm prosthesis in 47 patients. The maximum pressure gradient was 19.1(6.8) mmHg and effective valve orifice area was 1.47(0.27) cm2. At discharge and at follow-up, all patients were in New York Heart Association class I or II. At follow-up there was a significant reduction in pressure gradients, an increase in effective valve orifice areas, and decrease of pre-existing left ventricular hypertrophy. In conclusion, with controlled oversizing a gain in prosthesis size of 2 to 4 mm can be achieved. Implantation of oversized stentless valves leads to improved haemodynamics and to left ventricular remodelling in patients with a small aortic root.

Aged↗
PubMed1997

Abdominal aortic aneurysm repair during cardiopulmonary bypass: rationale for a combined approach.

Coronary artery disease and poor left ventricular function are the most important risk factors for morbidity and mortality in patients undergoing abdominal aortic aneurysm repair. Effective screening programmes and prior revascularization procedures (percutaneous translumincal coronary angiography and coronary artery bypass graft surgery) have helped to decrease the risk of cardiac-related adverse events. There is, however, a subgroup of patients presenting with both severe coronary artery disease and/or severely impaired left ventricular function and an acutely expanding or extremely large aneurysm that represents a therapeutic challenge. Surgery is often denied to these patients for their high risk. For this selected subgroup combined coronary artery bypass graft surgery and abdominal aortic aneurysm repair rather than a staged approach represents a therapeutic alternative. This article summarizes the pathophysiological concept, that favours a simultaneous approach performing abdominal aortic aneurysm repair during cardiopulmonary bypass and updates the current indications and results for this extensive surgery.

Aortic Aneurysm, Abdominal↗
PubMed1997

The influence of controlled mandatory ventilation (CMV), intermittent mandatory ventilation (IMV) and biphasic intermittent positive airway pressure (BIPAP) on duration of intubation and consumption of analgesics and sedatives. A prospective analysis in 596 patients following adult cardiac surgery.

The aim of the study was the determination of the influence of ventilation modes on the consumption of analgesics and sedatives, duration of intubation and pulmonary gas exchange. Assist/controlled mandatory ventilation (S-CMV, 123 patients), synchronized intermittent mandatory ventilation (S-IMV, 431 patients) and biphasic positive airway pressure ventilation (BIPAP, 42 patients) were compared in a prospective, controlled, open clinical trial over an 18-month period. Five hundred and ninety-six adult patients with normal pulmonary function before surgery and uneventful course following coronary artery bypass graft surgery were studied. Patients ventilated with BIPAP had a significantly shorter mean duration of intubation (10.1 h, P < 0.05) than patients treated with S-IMV (14.7 h) and S-CMV (13.2 h). In the S-CMV group, 39.9% of the patients required single or multiple doses of midazolam, but only 13.5% in the S-IMV group and 9.5% in the BIPAP group. The mean total amount of midazolam administered to these patients was significantly higher in the S-CMV group (8.8 mg) than in the S-IMV group (6.6 mg, P < 0.05) and in the BIPAP group (4.3 mg, P < 0.05). The consumption of pethidine and piritramide did not differ between S-CMV and S-IMV, but was significantly lower during BIPAP (P < 0.05). After extubation the patients' PaCO2 was highest in the S-CMV group. We conclude that ventilatory support with BIPAP reduces the consumption of analgesics and sedatives, and the duration of intubation. The possibility of unrestricted spontaneous breathing in all phases of the respiratory cycle is considered to be the reason. BIPAP seems to be an alternative to S-CMV and S-IMV in short-term ventilated patient.

Analgesics↗
PubMed1997

Trapped thrombus in a patent foramen ovale.

We report two cases of impending paradoxical embolism through a patent foramen ovale. A 73-year-old male had recurrent pulmonary embolism and a large thrombus trapped in a patent foramen ovale. The other patient, a 70-year-old male had septic mediastinitis after prior bypass surgery and a large thrombus lodged in a patent foramen ovale. Cardiac embolectomy and closure of the foramen ovale was performed in both cases because of impending paradoxical embolism. In addition pulmonary thromboendarterectomy was performed to relieve pulmonary hypertension. Therapeutical options are discussed.

Aged↗
PubMed1997

Ross-Konno operation with resection of endocardial fibroelastosis for critical aortic stenosis with borderline-sized left ventricle in neonates.

BACKGROUND: Critical aortic stenosis with severe concentric left ventricular hypertrophy and endocardial fibroelastosis has a substantial mortality rate when the conventional therapeutic strategy, ie, open surgical or balloon valvuloplasty, is applied. During the last decade, univentricular repair (Norwood operation) and heart transplantation have evolved as the only viable therapeutic options. An alternative in patients with borderline hypoplastic left heart syndrome consists of performance of a Ross-Konno operation with surgical enlargement of the left ventricular cavity, a procedure that has the advantage of achieving a two-ventricle repair. METHODS: Two neonates and 2 young infants with critical aortic stenosis, concentric left ventricular hypertrophy, and severe endocardial fibroelastosis, with echocardiographically documented antegrade flow in the ascending aorta, underwent a Ross-Konno operation combined with extensive endocardial and myocardial resection of the left ventricular septum and free wall. The incision in the ventricular septum was closed with a wide cuff of infundibular muscle that was harvested in continuity with the pulmonary autograft. RESULTS: In all 4 patients, the operation resulted in normal aortic valve function, marked reductions of width of the left ventricular septum (median, 6.5 mm, versus 11 mm preoperatively) and the left ventricular posterior free wall (median, 8.5 mm, versus 15.5 mm preoperatively), and enlargement of the left ventricular end-diastolic volume (median, 12.5 cm3, versus 6.5 cm3 preoperatively). Three patients had an uneventful recovery, with gradual improvement of left ventricular diastolic and systolic function during the first postoperative week; 1 neonate with associated mitral regurgitation died of left ventricular failure. CONCLUSIONS: The Ross-Konno procedure with resection of endocardial fibroelastosis may be a valuable adjunct for achieving a two-ventricle repair in borderline hypoplastic left heart syndrome. The operation results in enlargement of the left ventricular stroke volume and improvement of left ventricular diastolic function; in addition, resection of endocardial fibroelastosis relieves the mechanical impairment of myocardial function and therefore may promote the potential for left ventricular growth.

Aortic Valve Stenosis↗
PubMed1997

Discrepancy of sizers for conventional and stentless aortic valve implants.

BACKGROUND AND AIM OF THE STUDY: As the hemodynamic performance of an artificial heart valve is closely related to the size of the valve implanted, exact sizing of the prosthesis is important in aortic valve replacement. In the past, discrepancies have been recognized between the actual and labeled diameters of sizers used for conventional aortic valves; this study aimed to examine the accuracy of sizers for both conventional and stentless valves. METHODS: Currently used sets of sizers were analyzed using a high-precision digital micrometer with a resolution of 0.01 mm. Sizers of aortic bileaflet mechanical valves (ATS, CarboMedics, St. Jude Medical Standard, St. Jude Medical HP), conventional aortic bioprostheses (Carpentier Edwards) and stentless aortic bioprostheses (Freestyle, TorontoSPV) were analyzed. The diameters were recorded when the sizer could not be moved laterally while still able to be rotated. RESULTS: Results are given as mean +/- standard deviation for 20 repeat measurements. All mechanical valve sizers were 0.77 +/- 0.03 to 1.01 +/- 0.02 mm larger than labeled, whereas all bioprosthetic valve sizers proved to be sized as labeled (0 +/- 0.01 mm). CONCLUSIONS: Exact sizing is important in stentless valve replacement. The use of accurate sizers is recommended with other types of replacement valves as well. Results of valve replacement procedures worldwide would be more comparable if sizers of identical size were available in all operating rooms. As long as discrepancies between different sizers still exist, surgeons must be made aware of the problem.

Aortic Valve↗