Biomedical subjects

A Diegeler

Publications and source records attributed to A Diegeler.

65 records · Page 4Linked to original sources

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↗

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

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↗

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↗

PubMed1991

IMA-graft patency control by thermal coronary angiography during coronary bypass surgery.

Thermal coronary angiography (TCA) was evaluated for the intraoperative assessment of graft patency and flow in internal mammary artery (IMA) bypass grafts. TCA was performed in 210 patients undergoing 460 vein and 153 IMA bypass grafts after completion of the distal anastomoses. The IMA grafts and the recipient coronary arteries were delineated by the temperature differential between a cold epimyocardium and the perfusing warm blood after bulldog clamp release. TCA provided information about graft and anastomosis patency, initial flow patterns, and native coronary stenoses. TCA was performed in all studied IMA bypass grafts: 142 grafts were patent. Low flow but patency was observed in 24 IMA grafts and 11 IMA grafts showed no flow. Subsequently, 8 anastomotic failures and 3 proximal IMA graft occlusions were encountered. Based on these findings, 8 anastomoses were successfully revised and 7 additional vein grafts were added. One low flow IMA graft was not revised leading to postoperative ST elevation. Thirty-one distal native coronary stenoses were detected in the recipient LADs, 3 of which were not seen in the preoperative cineangiogram. In 20 instances, TCAs were obscured by an excess of fat or myocardium impeding image analysis. In 8 cases, TCA results were confirmed by conventional angiography postoperatively showing an excellent correlation in all cases. We conclude that intraoperative TCA demonstrates early IMA graft function and initial flow patterns. During our study, TCA documented a 7.2% IMA graft early failure rate. Intraoperative decision making was aided by TCA in 9.2% of all IMA grafts; this confirmed the clinical relevance of TCA.

Adult↗

PubMedDate not supplied

Excision of coronary artery fistula and coronary artery reconstruction without cardiopulmonary bypass.

In three patients, coronary artery fistulas originating from a conal branch of the mid-segment of the left anterior descending coronary artery (n = 2) and right coronary artery (n = 1) with drainage into the right atrium (n = 2) and right ventricle (n = 1) were successfully closed without the use of cardiopulmonary bypass. The use of a coronary artery stabilizer greatly facilitated the operation by immobilization of the fistula, its supplying coronary artery, and the regional myocardium. In selected patients, this technique allows secure closure of the fistula and meticulous reconstruction of the coronary artery without the use of cardiopulmonary bypass.

Adult↗