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Biomedical subjects

V Falk

Publications and source records attributed to V Falk.

At least 109 records · Page 6Linked to original sources
PubMed1996

The stentless Toronto SPV bioprosthesis for aortic valve replacement.

The Toronto SPV bioprosthesis for aortic valve replacement has been prospectively evaluated in 100 patients, since March 1993. Intraoperative transoesophageal and postoperative transthoracic echocardiography were used to assess valve function. Follow-up was complete in 74 patients at 6 months and in 38 patients at 1 year. The average valve size implanted was 26.5 mm. Some 37 patients had additional coronary artery bypass grafting surgery. The hospital mortality rate was 4%. Non-structural valve dysfunction occurred in one patient and late endocarditis in another patient required operation. There were no other valve complications. None of the patients developed clinically relevant aortic valve incompetence during follow-up and there was a significant decrease in pressure gradients, increase in valve orifice areas and decrease in left ventricular hypertrophy.

Aged↗
PubMed1996

Surgical treatment of abdominal aortic aneurysms of octogenarians.

The purpose of this study was to determine whether elective abdominal aortic aneurysmectomy in octogenarians is justified or may even be advisable. Between January 1986 and August 1993, 30 octogenarians of mean age 83.1 (range 80-93) years underwent abdominal aortic aneurysmectomy. Patients were divided into two groups: group 1 (n = 9) underwent elective surgical repair; group 2 (n = 21) underwent emergency procedure. In 28 patients location of the abdominal aortic aneurysm was infrarenal; two patients presented with a juxtarenal aneurysm. The average aneurysm diameter was similar in both groups (group 1, 68.8 mm; group 2, 83.5 mm, P = n.s.). In group 2, two patients had free peritoneal rupture, one presented with rupture into the duodenum and one with penetration into the vena cava. Rupture was confined to the retroperitoneum in another 15 patients. Two patients had an expanding aneurysm. Hospital mortality rate was zero in group 1 and 42.8% in group 2 (P = 0.011). Most early deaths were related to cardiac disease. The overall complication rate was 22% in group 1 and 62% in group 2. Mean intensive care unit time was 1.8 (range 1-3) days in group 1 and 3.6 (range 1-8) days in group 2 (P = 0.47). The 5-year survival rate was 67% in the electively managed group and 34% in the emergency group.

Aged↗
PubMed1996

Assessment of metabolic liver function and hepatic blood flow during cardiopulmonary bypass.

A modified monoethylglycinexylidide (MEGX) test was performed in 14 patients undergoing myocardial revascularization to evaluate liver function during cardiopulmonary bypass (CPB). MEGX is the principal metabolite of lidocaine. Different studies have shown a decrease in MEGX formation in patients with impaired liver function. Following a low-dose bolus application of 0.3 mg/kgBW lidocaine MEGX concentrations were measured in five-minute intervals for half an hour. This was done once before and once during CPB. Arterial and hepatic vein blood samples were obtained in order to avoid the effects of hemodilution by CPB priming. Hepatic blood was calculated using the indocyanine green (ICG) infusion extraction technique. MEGX formation during CPB decreased. After the 10 and 15 minutes measurement points the mean arterio-hepatic venous concentrations were 61 +/- 7.2 micrograms/L and 63 +/- 7.3 micrograms/L respectively in comparison to pre-CPB values of 36 +/- 5.8 micrograms/L and 42 +/- 5.1 micrograms/L. Hepatic blood flow increased insignificantly from a mean of 835 +/- 54 ml/min prior to CPB to 913 +/- 83 ml/min during CPB. As a result the MEGX clearance calculated 15 minutes after administration of lidocaine bolus application did not differ significantly before (51.2 +/- 6.4 micrograms/min) and during CPB (40.2 +/- 5.7 micrograms/min). In conclusion, a decrease in MEGX formation was found during CPB. However, due to increased hepatic blood flow there was no significant change in MEGX clearance before and during CPB.

Adult↗
PubMed1996

Resection of a thrombus floating in the aortic arch.

A 42-year-old patient had resection of two thrombi floating in the aorta under circulatory arrest. Atherosclerotic plaques in the isthmus and in the descending thoracic aorta predisposed the patient to thrombus formation. Intraoperative transesophageal echocardiography was used to guide the surgical approach.

Adult↗
PubMed1996

Echocardiographic monitoring of minimally invasive mitral valve surgery using an endoaortic clamp.

BACKGROUND AND AIMS OF THE STUDY: Twenty-four patients underwent minimally invasive mitral valve repair (n = 16) or mitral valve replacement (n = 8) using the Port-Access system. Intraoperative transesophageal echocardiography (TEE) was used in these patients to: (i) reassess valve pathology preoperatively; (ii) guide and continuously assess placement and position of the aortic endoclamp; (iii) measure aortic root diameters, aortic distensibility and aortic wall appearance prior to and after aortic endoclamping; (iv) evaluate the de-airing procedure; (v) evaluate the results of mitral valve repair; and (vi) guide weaning from cardiopulmonary bypass (CPB). METHODS AND RESULTS: Placement and positioning of the endoclamp was guided effectively in all but one patient who had acute retrograde aortic dissection with the onset of femoro-femoral bypass. The mean position of the tip of the endoclamp was 2.8 +/- 0.5 cm from the aortic valve annulus. The position was stable in all but five patients in whom repositioning and additional clamp volume were required. There was only a poor relationship between balloon volume and sinotubular junction diameter. The dynamic movement of the aorta was well preserved after clamping and the elasticity module did not change significantly (1.6 +/- 0.71 vs. 1.5 +/- 0.75 dynes x 10(6)/cm2). No intimal tears or wall edema was observed after clamp release. De-airing was incomplete in five patients, two of whom had transient ST-elevations with regional wall motion abnormalities. Weaning of CPB was therefore postponed until the ECG had normalized. All mitral valve repairs but one were successful (equal to or less than grade I residual mitral insufficiency). One patient with persistent grade II mitral insufficiency underwent valve replacement using the same approach. CONCLUSIONS: TEE can effectively guide minimally invasive mitral valve surgery using the Port-Access system. Placement and positioning of the endoclamp and its effects on the aortic wall can be evaluated. De-airing, weaning from CPB and the results of the procedure were effectively monitored using TEE.

Aorta↗
PubMed1996

Stentless bioprostheses for the small aortic root.

BACKGROUND AND AIMS OF THE STUDY: Despite a variety of different artificial heart valves no ideal prosthesis for the small aortic root is yet available. Conventional stented valves are hemodynamically disadvantageous because of higher transvalvular pressure gradients. Stentless bioprostheses were implanted in such patients to evaluate their performance as an alternative to homografts and to conventional mechanical prostheses. MATERIALS AND METHODS: We analyzed 57 patients with small aortic roots who underwent stentless aortic valve replacement (Toronto SPV) from March 1993 to November 1995. All but two patients had aortic stenosis. The mean age at operation was 70.9 (+/-8.2) years. The annular diameter was 18-23 mm (mean 21.4 +/- 1.1 mm) in all patients. Of the 57 patients, 17 received a 23 mm and 40 patients a 25 mm prosthesis. RESULTS: Using the oversizing technique, valve size was adjusted according to the sinotubular junction diameter, allowing a gain in prosthesis size of 2-4 mm to be achieved in all patients. On pre-discharge echocardiography maximum flow velocity was 2.3 +/- 0.4 m/s, maximum pressure gradient was 19.1 +/- 6.8 mmHg, and effective valve orifice area was 1.46 +/- 0.27 cm2. All patients were in NYHA class I or II at discharge. One patient was reoperated due to a folded annulus caused by too much oversizing. At six months follow up there was a significant reduction in pressure gradients and an increase in effective valve orifice areas in relation to a decrease in pre-existing left ventricular hypertrophy. CONCLUSIONS: Stentless bioprostheses show excellent hemodynamics due to their comparably large internal diameter and flexibility. Controlled oversizing is a safe technique without additional complications. As larger valve sizes can be implanted, aortic root enlargement is not necessary. The superior hemodynamic profile of stentless aortic valves is especially advantageous in patients with small aortic roots.

Aged↗
PubMed1996

[Value of score systems in heart surgery].

Although numerous scores have been designed to provide stratification of morbidity and mortality outcome by preoperative risk factors and to determine patients at risk from prolonged length of ICU and hospital stay after cardiac surgery, the predictive power of these scores for individual prognosis remains poor. However, scoring in cardiac surgery may be used for a different purpose. With increasing health care costs fast-track intensive care treatment saving ICU resources has become an important issue in cardiac surgery. With the help of scoring systems that can accurately identify low-risk patients who will have a favourable postoperative course a subset of patients eligible for early ward referral can be defined. Thus, scoring may save total ICU days of cardiac surgical patients and reduce costs.

Cause of Death↗
PubMed1995

One-stage surgery of coronary arteries and abdominal aorta in patients with impaired left ventricular function.

BACKGROUND: Coronary artery disease (CAD) is common in patients with abdominal aortic aneurysms (AAA). Some patients will present with the combination of unstable angina, impaired left ventricular function, and a large symptomatic (ie, leaking, expanding) AAA. In this subgroup of high-risk patients, aortic cross-clamping may have a deleterious effect on cardiac function, whereas coronary artery bypass graft surgery before aneurysmectomy (staged operation) carries the risk of perioperative aneurysm rupture. One-stage surgery, ie, myocardial revascularization and simultaneous aortic aneurysm repair, has been proposed in this situation. This article summarizes our results with the combined one-stage approach in patients with symptomatic CAD, impaired left ventricular function, and large symptomatic aortic aneurysms or severe aortic occlusive disease. As yet, this cohort is the largest reported in the English literature. METHODS AND RESULTS: In 25 patients (24 men) with a mean age of 69.4 years (range, 55 to 80 years), we performed combined open heart and intra-abdominal aortic surgery. Eighteen patients had severe three-vessel disease and impaired left ventricular function (ejection fraction, < 35%). In addition, 3 of these patients had severe aortic valvular stenosis and/or insufficiency. Seven patients had one- or two-vessel disease with a low left ventricular ejection fraction in the range of 15% to 30%. All patients were in New York Heart Association functional class III or IV. Twenty-one of 25 patients had symptomatic infrarenal AAA (perianeurysm hematoma was present in 9 patients, and 12 patients had signs of beginning perforation). Four patients with aortoiliac occlusive disease and limb ischemia were simultaneously operated on. The surgical procedure started with the performance of coronary artery bypass graft surgery. After completion of myocardial revascularization, aortic aneurysm repair was performed while extracorporeal circulation was continued for mechanical cardiac assist until aortic surgery was fully accomplished. An average of 3.3 (3 to 5) coronary bypass grafts were placed, including 17 internal thoracic artery grafts. In addition, three aortic valves were replaced. In the abdominal aortic position, 12 straight tube grafts and 13 bifurcation grafts were implanted, and three renal and two carotid arteries were simultaneously repaired. The total time of surgery varied from 2.3 to 8.5 hours, with a mean time of 3.9 +/- 1.4 hours. One intraoperative myocardial infarction occurred despite open grafts. Intensive care unit treatment lasted 1 to 13 days, with a mean of 3.6 +/- 2.5 days. Three patients (12%) died after surgery--1 because of acute renal failure induced by an adverse reaction to heparin, 1 because of myocardial infarction, and 1 because of multiorgan failure. One-year actuarial survival rate was 88%, which compares favorably with survival after isolated AAA surgery in this high-risk patient subgroup and equals survival in patients with severe CAD and severely depressed myocardial function. CONCLUSIONS: One-stage surgery is a possible approach to highly symptomatic patients with severe multivascular disease and has acceptable early morbidity and mortality. Patients with severely impaired left ventricular function and unstable CAD carry a high risk of left heart failure and/or myocardial infarction during abdominal aortic surgery. Extracorporeal circulation protects the heart from the hemodynamic changes after aortic clamping or declamping during abdominal aortic surgery. The present study demonstrates that one-stage procedure is a reasonable option for this patient subgroup.

Aged↗
PubMed1995

True aneurysm of the superior gluteal artery: case report and review of the literature.

Aneurysms of the gluteal arteries are rare and mostly are caused by pelvic fractures or penetrating injuries. As such these aneurysms are pseudoaneurysms. As an absolute rarity we report the case of a 43-year-old man with a histologically verified 5 cm-diameter, true saccular aneurysm of the left superior gluteal artery. The patient was admitted with 6-weeks ongoing sciatic pain without previous trauma. He was scheduled for surgery because an initial attempt of transcatheter embolization failed. By dividing the origin of the gluteus maximus muscle from the iliac crest, the aneurysm was exposed at the pelvic outlet by an extrapelvic approach and was excluded by endoaneurysmorrhaphy. Uncontrolled bleeding was prevented by temporary occlusion of the left iliac artery by a percutaneously inserted balloon catheter, thus avoiding an additional retroperitoneal approach. The postoperative course was uneventful, and sciatic pain had resolved completely. The chosen strategy provides safe and successful surgical management of gluteal artery aneurysms.

Adult↗
PubMed1995

Simultaneous coronary bypass and abdominal aortic surgery in patients with severe coronary disease--indication and results.

In patients with severe coronary artery disease (CAD) abdominal aortic surgery is still associated with high morbidity and mortality rates. Some patients will present with both symptomatic CAD and large, symptomatic abdominal aortic aneurysms (AAA) or end-stage aortic occlusive disease (AOD) that does not allow for a two-stage procedure. We report a series of 29 patients who underwent simultaneous coronary artery bypass graft surgery (CABG) and abdominal aortic surgery (25 AAA, 4 AOD). In the AAA group there were 23 males and 2 females with a mean age of 68 years (50-80). Sixteen patients presented with severe three-vessel disease. Ten patients had unstable angina. Aortic stenosis or insufficiency was present in two and one patient, respectively. Four patients with three-vessel disease and an ejection fraction below 30% presented with end-stage AOD and critical limb ischemia. Coronary bypass graft surgery was performed first. With the patient still on partial cardiopulmonary bypass, abdominal aortic surgery was carried out. Patients received an average of 3.1 coronary bypass grafts. Additionally, three aortic valves were implanted. Fourteen tube grafts and 15 bi-iliacal or bifemoral bifurcation grafts were placed in the abdominal aortic position. Additional vascular surgery was performed in five patients. Intraoperative management was without complication in all but one patient, who had intraoperative myocardial infarction (AOD group). Hospital mortality was 8% (2/25) in the AAA group. There was however substantial hospital morbidity (52.2%). The mean follow-up is 20.5 +/- 2.5 months. The actuarial survival rate at 3 years is 84.9%. It is concluded that combined CABG and abdominal aortic surgery is a reasonable option for patients who present with both severe CAD and symptomatic abdominal aortic disease. The continuation of CPB during aortic surgery may effectively prevent the adverse effects of infrarenal aortic clamping on a failing ventricle.

Actuarial Analysis↗
PubMed1995

Open heart surgery in the octogenarians--a study on long-term survival and quality of life.

This retrospective study analyzes the perioperative and long-term survival rate as well as the long-term quality of life of 54 patients (23 f/31 m), aged 80 years or older (80 to 87, mean 82.2, SD +/- 1.79 years), who underwent open heart surgery between January 1986 and December 1993. There were 23 patients with coronary bypass, 21 with aortic valve replacement, 1 with mitral valve replacement, 8 with combined aortic valve replacement and coronary bypass, and 1 with double valve replacement. Preoperatively, 26 of the patients were in New York Heart Association (NYHA) class IV, 28 patients in class III. The in-hospital mortality was 9.3% (5/54) over all and 6.1% (3/49) for elective procedures. Follow-up time ranged from 6 to 91 months (mean 26.2 +/- 16.5). Of 49 discharged patients, 6 (12.2%) died during the follow-up period. At the time of re-evaluation 21 patients were in NYHA class I, 24 patients in class II, and 4 in class III. There was a significant long-term benefit from the surgical intervention in 39 or the 54 patients. Of 43 survivors 41 were able to live on their own and 38 were able to handle their daily routine without help. Two patients were cared for in a nursing home. This long-term analysis demonstrates the benefits of cardiovascular surgery in octogenarians in terms of social integration and quality of life.

Aged↗
PubMed1995

Tonsillar carcinoma in the early postoperative course following heart transplantation.

A 45-year-old male with end-stage dilative cardiomyopathy was referred for heart transplantation (HTx). Apart from severe heart disease the patient had an unremarkable medical history. Risk factors were heavy smoking and moderate consumption of alcohol. Preoperative screening including a thorough ENT status did not reveal any other risk factor or contraindication for heart transplantation. HTx was performed three months later. Immunosuppressive therapy consisted of triple-drug therapy and induction therapy with antithymocyte globulin. The patient had an uneventful perioperative course. One month after transplantation the patient developed a rapidly growing squamous cell carcinoma of the left tonsil with local metastasis. Because of the rapid growth and size of the tumor surgical treatment was already impossible at that early time. Despite a course of chemotherapy the tumor continued to grow; treatment was changed to radiation therapy resulting in partial remission. Cyclosporine and azathioprine dosages were reduced at the same time. 9 months following HTx the patient developed a rapidly growing recurrence. As there were no further therapeutic options, immunosuppressive therapy was completely discontinued with the patient's agreement. He died 2 months later. The rapid tumor growth and its early manifestation following HTx suggest a preexistent occult carcinoma. A more extensive and repetitive preoperative screening in HTx candidates who are heavy smokers should be considered.

Carcinoma, Squamous Cell↗
PubMed1995

Thermal coronary angiography for intraoperative patency control of arterial and saphenous vein coronary artery bypass grafts: results in 370 patients.

BACKGROUND AND AIM OF THE STUDY: Early graft failure is often associated with technical failures and is therefore potentially avoidable. We used thermal coronary angiography (TCA) for intraoperative graft patency control in 370 patients undergoing routine coronary artery bypass graft surgery to determine whether consequent intraoperative bypass graft control may result in improved patency rates. METHODS: The temperature differences generated in between the myocardium and the grafts by injecting cold cardioplegic solution into the proximal end of a vein graft or by warmer blood running through an internal thoracic artery (ITA) graft were detected using three different infrared camera systems. The resulting "heat pictures" were evaluated for anastomotic patency and to outline graft anatomy. RESULTS: A total of 693 vein grafts were visualized. In 9.4% TCA failed to produce usable images. In the remaining 628 grafts, TCA revealed intraoperative patency in 98.8%. Out of 370 ITA grafts, only 14 could not be sufficiently visualized by TCA. Nineteen ITA occlusions (5.3%) were found: 5 intimal flaps; 11 suture imposed strictures; and 3 proximal ITA occlusions. All occluded grafts were subsequently revised or replaced. All sequential ITA as well as 15 right ITA grafts proved to have patent anastomoses. CONCLUSION: Using TCA an early graft dysfunction rate of 1% for vein grafts and 5.3% for ITA grafts could be demonstrated. Most occlusions were due to technical mistakes at the distal anastomosis. TCA outlines grafts and the attached coronaries by temperature differences without the need for a contrast agent. There is no interference with the surgical procedure. It is an ideal, noninvasive method to immediately document the success or failure of myocardial revascularization.

Adult↗
PubMed1995

The Toronto SPV bioprosthesis: one-year results in 100 patients.

BACKGROUND: We studied the long-term results of heart valve replacement with the Toronto SPV bioprosthesis. METHODS: From March 1993 until July 1994 the Toronto stentless bioprosthesis was implanted in 100 selected patients with a mean age of 70.7 years. The predominant aortic valve lesion was stenosis in 94 and insufficiency in 6 cases. Eighty-eight patients received a valve 25 mm in diameter or larger. Additional coronary artery bypass grafting was performed in 37 cases. Hospital mortality was 4%. Seventy-four patients were seen at 6 months and 38 patients at 1 year follow-up. RESULTS: Structural deterioration, thromboembolism or hemorrhage were not encountered. Nonstructural dysfunction lead to reoperation in 1 patient. Another patient presented with endocarditis at 1 year postoperatively. There were no other valve-related complications. Echocardiographic mean pressure gradients ranged from 7.7 to 11.1 mm Hg postoperatively. There was a significant decrease in pressure gradients at 6 months of follow-up. Minimal aortic valve incompetence was seen in 3 patients. CONCLUSIONS: The Toronto stentless bioprosthesis has superior hemodynamics and is an excellent alternative to conventional stented bioprostheses. Long-term evaluation has to prove whether this promising new valve can live up to its expectations.

Adult↗
PubMed1994

The effect of coronary bypass graft surgery for the prevention of sudden cardiac death: recurrent episodes after ICD implantation and review of literature.

Sudden cardiac death (SCD) accounts for at least 50% of the mortality of patients with ischemic heart failure. Ventricular arrhythmias are responsible for most cases of sudden cardiac death. There is some evidence that coronary artery bypass graft (CABG) surgery may reduce the incidence of recurrent episodes of SCD by prevention of myocardial ischemia. To test the hypothesis that CABG surgery is effective in the prevention of SCD, we compared the recordings of implantable cardioverter defibrillators (ICD) in patients who underwent ICD implantation alone (n = 64) or ICD implantation and concomitant CABG surgery respectively (n = 11). All patients had experienced out of hospital cardiac arrest. ICD recordings were obtained every 3 months and the number of recurrent episodes of ventricular tachycardia (VT) for each time period was noted. Three months following ICD implantation patients in the surgically treated group had an average of one episode of VT per patient as compared to 2.7 episodes in the nonsurgical group. This difference was observed during the following months as well. However, at no time (up to 18 months of follow-up) this difference reached statistical significance. There were no deaths in the surgically treated group. Although we could not demonstrate a statistical significant difference between the two groups, there was a tendency in the surgically treated group to have less episodes of recurrent VT than in the medically treated group. We, therefore, conclude that survivors of SCD presenting with multivessel coronary artery disease (CAD) should undergo coronary artery bypass grafting to prevent myocardial ischemia as the triggering event for lethal ventricular arrhythmias.

Coronary Artery Bypass↗
PubMed1994

Intraoperative assessment of internal mammary artery bypass graft patency by thermal coronary angiography.

Following early graft failure in some patients during routine use of the internal mammary artery in coronary bypass surgery, a thermal coronary angiography technique was used for direct intraoperative control of internal mammary artery graft patency. This non-invasive method allows the evaluation of graft patency, anastomotic integrity and initial flow patterns without compromising the conduct of the surgical procedure. Internal mammary artery graft patency was controlled by thermal coronary angiography in 348 patients undergoing coronary bypass surgery. Graft anatomy, perfusion and distal run-off in the recipient native coronary artery was delineated by thermal coronary angiography using the temperature gradient of the warm perfusing blood and the cold myocardium. Thermal coronary angiograms were evaluated for graft and anastomotic patency as well as for direction and magnitude of internal mammary artery flow in the native coronaries. Some 348 internal mammary artery grafts, including 13 sequential grafts, were evaluated. Thermal coronary angiography failed for technical or logistical reasons in seven of 348 cases (2.0%). Thermal coronary angiography documented optimal anterograde flow in 282 of 341 cases (82.7%), reduced anterograde flow in 38 of 341 (11.1%) and no anterograde flow in 21 of 341 (6.2%). Using this approach 21 internal mammary artery graft occlusions were discovered, 18 at the anastomotic site and three at the site of the previously placed bulldog clamp. In addition, six unexpected distal native coronary stenoses and three internal mammary artery graft spasms were detected by thermal coronary angiography and found to be responsible for impaired anterograde flow. Based on these findings, 16 anastomotic revisions, nine additional vein grafts and two additional vein patches were performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗