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Biomedical subjects

K Bayazit

Publications and source records attributed to K Bayazit.

At least 19 recordsLinked to original sources
PubMed2001

Approach to sinus of Valsalva aneurysms: a review of 53 cases.

OBJECTIVE: The reported experience with sinus of Valsalva aneurysms (SVAs) is limited. Our approach to this subset of patients and an algorithm-dependent classification are presented. METHODS: Between 1985 and 2000, 53 patients (mean age: 24+/-12; range 4--60) underwent repair for ruptured (64%) or non-ruptured (36%) SVA. Associated lesions were present in 21 patients; VSD in 18, moderate to severe aortic insufficiency in five, aortic stenosis in four (two subaortic membrane and one bicuspid valve), PDA in two, mitral insufficiency in one, tetralogy of Fallot in one and endocarditis in one. Operative procedures included simple or Teflon pledgetted direct suturing (31 cases; 58%), patch repair (21 cases; 40%), and stentless porcine bioprosthetic aortic root replacement in a case with extensive involvement and aortic root distortion (2%). Concomitant procedures were VSD repair in 18 patients, aortic valve replacement in four, aortic valve resuspension in three, subaortic membrane resection in two, PDA ligation in two, mitral annuloplasty in one and total correction in one. RESULTS: Early mortality was 1.9%. A permanent pacemaker was inserted in one patient due to complete heart block. The survivors were followed up for 8.2+/-5 years (range: 21 days to 15 years). There were three reoperations due to suture dehiscence; patch repair was undertaken in these patients with no further unfavorable consequences. All patients were in NYHA Class I or II as of their last follow-up. CONCLUSIONS: Repair of SVA can be performed with an acceptably low operative risk and a good symptom-free long-term outcome expectation. Echocardiography provides all the necessary details for diagnosis. Dual exposure/patch repair strategy is advocated in the ruptured cases.

Adult↗
PubMed2000

Coronary artery bypass grafting in the conscious patient without endotracheal general anesthesia.

BACKGROUND: Over the past several years, considerable experience has accumulated in performing coronary anastomoses on the beating heart, and various aspects of minimally invasive approaches have been simplified. In an attempt to further simplify and decrease the "invasiveness" of this procedure, performing this operation without endotracheal general anesthesia was deemed feasible in certain subsets of patients. METHODS: Between October 1998 and June 1999, 5 patients underwent coronary artery bypass grafting without endotracheal general anesthesia, using high thoracic epidural block to construct extension grafts with a short segment of radial artery, between the in situ left or right internal thoracic arteries and the left anterior descending (n = 4) or right coronary arteries (n = 1). There were 2 female and 3 male patients, with a mean age of 67.4 +/- 8.3 years. RESULTS: The perioperative course of the patients was uneventful. There was no perioperative morbidity or mortality. No patient was converted to general anesthesia or to conventional operation. Control angiograms revealed patent anastomoses in all patients. In 1 patient, spasm of the radial artery graft was observed that was relieved 3 weeks later spontaneously. Mean length of hospital stay was 2.2 +/- 0.4 days. All patients were symptom free and returned to normal daily life at the first postoperative month. CONCLUSIONS: Our initial experience confirms the feasibility of performing coronary bypass grafting in the conscious patient without endotracheal general anesthesia.

Aged↗
PubMed1999

Minimally invasive mitral valve surgery: the subxiphoid approach.

BACKGROUND: This report describes mitral valve replacement using a unique subxiphoid approach with a lower ministernotomy and a skin crease incision and compares the operative and echocardiographic results to patients undergoing mitral valve replacements using previously described strategies. METHODS: Fifty-four patients underwent mitral valve replacement using a subxiphoid approach (group 1); 32 patients underwent mitral valve replacement, 11 patients underwent mitral valve replacement + tricuspid reconstruction, 2 patients underwent mitral valve replacement + tricuspid valve replacement, and 9 patients underwent mitral reconstruction. This group of patients was compared to 11 patients who underwent mitral valve replacement through a superior ministernotomy (group 2) and 29 patients who underwent mitral valve replacement with full median sternotomy (group 3, 22 mitral valve replacements, 2 mitral valve replacements + tricuspid reconstruction, 2 mitral reconstructions, and 3 mitral reconstructions + tricuspid reconstruction). RESULTS: There was no operative mortality in all groups. The operation lasted significantly longer in group 2 patients compared to group 1 and 3 patients (p < 0.01). Postoperative mediastinal drainage was significantly lower in groups 1 and 2 (p < 0.001). Pain assessment revealed no difference between the groups. Three patients in group 1 presented with pericardial effusion. Except for this complication, early postoperative echocardiographic findings of the patients were similar in all three groups. All patients were in New York Heart Association functional class I or II at the second postoperative month, irrespective of the surgical technique used. CONCLUSIONS: There was no prominent superiority of the ministernotomy approaches over the standard median sternotomy approach. However, the reliability of the subxiphoid approach is documented echocardiographically and any type of mitral replacement can be performed with this approach.

Adult↗
PubMed1999

Carotid disease in patients scheduled for coronary artery bypass: analysis of 678 patients.

The purpose of this article is to investigate the frequency of carotid disease and to identify high-risk groups among patients scheduled for isolated coronary artery bypass grafting (CABG) procedures under nonemergent conditions. A total of 678 consecutive patients underwent preoperative carotid artery duplex scanning (CADS) before CABG procedures. Morphology of carotid artery was determined and five groups were formed. Age, sex, cervical bruit, diabetes mellitus (DM), hypertension, smoking, history of cerebrovascular event (CVE), peripheral vascular disease (PVD), and severity of coronary artery disease were investigated to describe the high-risk group for carotid artery disease. In 41% of patients carotid examination produced normal findings; 46.2% had less than 60% luminal stenoses, 7.1% had 60-79% stenoses, 4.6% had 80-99% stenoses, and 1.2% had total occlusion. Previous cerebral ischemic events (CVE) (p<0.05), hypertension (p < 0.01), smoking (p < 0.01), advanced age (p < 0.01), and female sex (p < 0.01) were identified as high-risk factors for carotid artery stenoses. There was a linear association between carotid disease and coronary disease (p < 0.05). Documentation of previous CVE, hypertension, smoking, advanced age, female sex, and severe coronary artery disease may be helpful in identifying patients at high risk for carotid artery stenoses.

Adult↗
PubMed1999

Experimental evaluation of retrograde cerebral perfusion by single photon emission computed tomography technique (SPECT).

BACKGROUND: Protection of the brain is of vital importance during aortic arch aneurysms. In this study efficiency of retrograde cerebral perfusion was evaluated with the use of single photon emission computed tomography technique (SPECT) by using 99mTc hexamethylpropylene amine oxime (HMPAO). METHODS: Four animals were used. The internal maxillary vein was the site of retrograde cerebral perfusion. The animals were studied after the heart rate and respiration were stopped with the use of the high dose drug administration and the brain was perfused with cold Ringer's lactated solution. After this procedure, 99mTc HMPAO-SPECT study was performed. RESULTS: In one animal we did not get any cerebral image because of the competent venous valve in the internal maxillary vein. In the remaining animals, normal brain perfusion was achieved. CONCLUSIONS: 99mTc HMPAO-SPECT study documented that blood flow via the retrograde way meets the metabolic demand of the brain. Retrograde delivery of 99mTc HMPAO did not conclude any poorly perfused area in the brain when in given both sides and all parts of the brain can be effectively perfused by cerebral venous system in hypothermic conditions.

Animals↗
PubMed1999

Low-dose oral anticoagulation and antiplatelet therapy with St. Jude Medical heart valve prosthesis.

BACKGROUND AND AIM OF THE STUDY: Since 1986, the St. Jude Medical (SJM) mechanical heart valve prosthesis has been implanted in patients at the authors' institution. We present our experience of low-dose oral anticoagulation and antiplatelet therapy following SJM valve implantation. METHODS: Among 2,585 patients (mean age 40.3 +/- 13.5 years) living in a rural environment, 865 underwent aortic valve replacement (AVR), 1,231 mitral valve replacement (MVR) and 489 double valve replacement (DVR). All patients received 2.5 mg/day warfarin and a combination of antiaggregation therapy (dypridamole 3 x 75 mg/day plus aspirin 100 mg/day), irrespective of their prothrombin time and cardiac rhythm. RESULTS: Postoperatively, 139 adverse events occurred (51 in AVR patients, 58 in MVR, 30 in DVR). Operative mortality rate was 5.9%, 4.7% and 6.1%, respectively, in the three groups (overall mortality rate 5.4%). The most frequent cause of operative mortality was low cardiac output. During follow up, there were 88 anticoagulant hemorrhages (1.2%/patient-year (pt-yr)), 11 paravalvular leaks (0.2%/pt-yr), 52 thromboembolisms (0.7%/pt-yr), 60 mechanical valve thromboses (0.8%/pt-yr) and 78 reoperations (1.1%/pt-yr). These complications occurred in 101 patients after AVR, in 125 after MVR, and in 63 after DVR (4.2%, 3.7% and 4.6% per pt-yr, respectively). Patient age (p = 0.0004), concomitant surgery (p = 0.0017) and late valve-related complications (p = 0.0159) were statistically significant mortality factors after AVR. Previous surgery was a significant risk factor for operative mortality after MVR (p <0.05). Female gender (p = 0.0059) and age (p = 0.017) were significant risk factors for operative mortality after DVR (p <0.01). CONCLUSIONS: Following implantation of the St. Jude Medical mechanical heart valve prosthesis, a fixed dose of 2.5 mg/day warfarin and combined dipyridamole/aspirin provided satisfactory results in terms of thrombosis, embolism and bleeding.

Administration, Oral↗
PubMed1999

Minimally invasive replacement of ascending aortic aneurysms: intermediate term results.

BACKGROUND: Minimally invasive techniques have gained recent interest in the realm of cardiac surgery. This report describes our initial experience with graft replacement of ascending aortic aneurysms using a superior mini-sternotomy approach. METHODS: Between March 1997 and October 1997, four patients underwent operation for ascending aortic aneurysm via superior mini-sternotomy approach. There were two female and two male patients, ranging in age from 52 to 62 years (mean 53.7 +/- 7.6). All patients had the stigmata of Marfan's syndrome. Mean diameter of the ascending aortas was 6.1 +/- 0.9 cm. Composite graft replacement with coronary reimplantation was performed in all cases. In one patient hemiarch replacement was performed under total circulatory arrest. There was no hospital (30-day) mortality. Mean aortic cross clamp and cardiopulmonary bypass times were 63 +/- 14.1 minutes (range 44 to 78) and 116.7 +/- 43.3 minutes (range 81 to 177), respectively. One patient was re-explored for bleeding. RESULTS: Lengths of hospital stay ranged from 5 to 7 days (mean 5.5 +/- 1). Patients were followed-up for at least 18 months. One patient suffered a fatal stroke in her third postoperative month. All surviving patients were in NYHA Class I at the sixth postoperative month and thereafter. CONCLUSIONS: Minimally invasive graft replacement of ascending aortic aneurysms can be performed safely and effectively. Long term results are likely to be similar to those of conventional cases performed through a full median sternotomy.

Aged↗
PubMed1998

Optimization of synchronization delay in latissimus dorsi dynamic cardiomyoplasty.

BACKGROUND: Optimal synchronization delay (SD) for triggering the implanted cardiomyostimulators in patients undergoing latissimus dorsi dynamic cardiomyoplasty has not been clearly defined. Generally a synchronization delay time of 45 to 60 ms is used in the current practice, in which the implanted cardiomyostimulator stimulates the latissimus dorsi muscle 45 to 60 ms after mitral valve closure acquired with M-mode echocardiography. We investigated the effect of shortening or prolonging the delay time on cardiac functions. METHODS: We studied 10 patients who were in their first 2 years postoperatively. Three values for SD (SD = 0 ms, 45 to 60 ms, and 150 to 160 ms) were echocardiographically evaluated for their influence on both systolic and diastolic left ventricular parameters. RESULTS: Ejection fractions were 0.27 +/- 0.07, 0.28 +/- 0.07, and 0.32 +/- 0.06; peak aortic velocities were 0.85 +/- 0.8, 0.86 +/- 0.11, and 0.92 +/- 0.8 m/s; and velocity-time integrals were 0.16 +/- 0.03, 0.16 +/- 0.03, and 0.19 +/- 0.03 m for the SD values of 0, 45 to 60 ms, and 150 to 160 ms, respectively. Diastolic parameters were also measured. Isovolumetric diastolic relaxation time was 97.5 +/- 49, 97.20 +/- 44, and 111.8 +/- 49 ms; deceleration time was 83.67 +/- 32, 88.48 +/- 35, and 92.68 +/- 34 ms; and ratio or velocity-time integral of e wave to velocity-time integral of a wave was 3.09 +/- 0.98, 2.48 +/- 0.69, and 2.38 +/- 0.65 for the SD values of 0, 45 to 60 ms, and 150 to 160 ms, respectively. Systolic functions were better when SD was set at 150 to 160 ms, but there was a diastolic compromise. On the other hand, diastolic parameters were more favorable when SD = 0 (i.e., cardiomyostimulator triggered without delay) but the systolic assist was suboptimal. Systolic and diastolic parameters seemed relatively well-balanced with the current practice of setting the synchronization delay at 45 to 60 ms. CONCLUSIONS: The most favorable systolic effects were obtained with a prolonged delay of synchronization (150 to 160 ms), at some expense of diastolic functions. On the other hand, with a short or absent delay, diastolic parameters were improved but systolic parameters became suboptimal. Therefore, the current practice of setting the SD between 45 and 60 ms after echocardiographic mitral valve closure is suggested for the optimal timing for cardiomyostimulator stimulation in patients who have undergone latissimus dorsi dynamic cardiomyoplasty. Yet a great deal of individualization is necessary, and fixed preset values cannot definitely be determined because one setting does not fit all patients.

Aorta↗
PubMed1998

Coronary artery bypass grafting on the beating heart without the use of extracorporeal circulation: review of 2052 cases.

OBJECTIVE: A total of 2052 patients operated on with the off-pump technique (coronary artery bypass grafting on the beating heart without the use of extracorporeal circulation) between June 1993 and March 1996 are retrospectively reviewed. Predictors for early mortality, perioperative myocardial infarction, and low cardiac output state were statistically analyzed. METHOD: Our indications for an off-pump procedure were either patients with technically suitable coronary lesions (the vast majority) or patients who could not tolerate cannulation, hypothermia, or cardiopulmonary bypass because of the poor left ventricular function (198 patients) and/or associated diseases or conditions (73 patients). RESULTS: Overall operative mortality was 1.9% and perioperative myocardial infarction occurred in 59 patients (2.9%). According to logistic regression analysis, associated bronchial asthma (p = 0.0001), hypertension (p = 0.05), poor quality of the left anterior descending artery (p = 0.02), and ungrafted circumflex coronary artery disease (p = 0.007) were the early mortality predictors. Nonbypassed circumflex disease was also associated with a high incidence of perioperative myocardial infarction and low cardiac output state. No homologous blood or packed red cell transfusion was required in 74.2% of the patients. CONCLUSION: On the basis of the presented data, off-pump coronary artery bypass grafting appeared to be a safe and effective technique in selected patients with appropriate coronary lesions.

Adult↗
PubMed1998

Left ventricular aneurysm repair: an assessment of surgical treatment modalities.

OBJECTIVE: Different closure techniques (linear vs. circular), as well as the efficacy of revascularization in the left ventricular aneurysm repair, with regard to immediate and mid-term results, were assessed and factors having influence on the early mortality and morbidity and survival were analyzed. METHOD: Between January 1991 and November 1996, 248 patients underwent surgical repair for postischemic left ventricular aneurysm. A total of 26 of them were female (10.50%). Linear closure was employed in 121 patients (48.8 %) and circular (patch endoaneurysmorraphy) closure in 127 (51.2%). Coronary revascularization was added in 203 (81.9%) cases. Patients were followed for an average follow-up time of 39.3 months. RESULTS: Early mortality rate was 6% (15 patients). The difference in mortality rate by the repair method was not statistically significant (8.3% in the linear closure group and 3.9% in the circular closure group, P = 0.15). Absence of preoperative angina pectoris (P = 0.029), dyspnea as the presenting symptom, a preoperative left ventricular segmental wall motion scoring of 14 or greater, a cardiopulmonary bypass duration exceeding 2 h (P = 0.004), an aortic clamping time exceeding 1 h (P = 0.026) were associated with early mortality. Concomitant coronary revascularization had no effect on early mortality. However, low cardiac output state was less frequent in patients with concomitant coronary revascularization (P = 0.022). Functional status improved in both groups. Follow-up extending to 81st month revealed no difference in survival between the groups (84% for linear closure group and 92% in circular closure group, including operative mortality, P = 0.12). However, functional status improvement was better in the patients who underwent circular repair (P = 0.0077). Revascularization appeared as having no important influence on both survival and functional status. A preoperative left ventricular segmental wall motion scoring of 14 or greater was associated with a higher incidence of early mortality, low cardiac output syndrome and poor long-term survival. CONCLUSION: Left ventricular aneurysm repair is an important therapeutic intervention and can be performed with reliable results, regardless of repair method, either linear or circular. Long term results revealed better functional status in circular repair group. Concomitant coronary revascularization reduced the incidence of low cardiac output state. Performance of the unaffected regions of myocardium was found to be an important determinant of both early and late outcome.

Adolescent↗
PubMed1998

Bloodstream, respiratory, and deep surgical wound infections after open heart surgery.

Nosocomial infections are one of the most feared complications after open heart surgery. A large retrospective study was conducted to evaluate the nature and scope of the problem. Between 1992 and 1998, 9352 patients who had undergone open heart surgery were evaluated. Bloodstream infections, pneumonia, and deep sternal wound infections were included. Univariate and logistic regression analyses were conducted to identify the high-risk patients that were likely to become infected. Three hundred forty-six infections in 276 patients were diagnosed. Age, preoperative albumin level, banked blood requirement, duration of operation, diabetes mellitus, previous open heart surgery, moderate or severe pericardial adhesions, obesity, postoperative low cardiac output, and postoperative cerebrovascular accident were found to be significant in univariate and logistic regression analyses for infectious outcome. Univariate analysis also revealed additional significant factors: fresh frozen plasma requirement, duration of cardiopulmonary bypass and cross-clamp, preoperative high levels of blood urea and glucose, presence of occlusive peripheral arterial disease, preoperative history of hypertension, and nasal carriage of Staphylococcus aureus. Methicillin resistant S. aureus was involved in 58.4% of the infections. Risk factors should be individualized for patients and every effort should be carried out to minimize infectious outcome.

Adolescent↗
PubMed1998

Mitral valve replacement with St. Jude Medical prosthesis and low-dose anticoagulation in patients aged over 50 years.

BACKGROUND AND AIMS OF THE STUDY: These studies were designed to assess the effect of low-dose anticoagulation in elderly patients after mitral valve replacement. METHODS: Between 1986 and 1995, 250 patients aged > or = 50 years underwent isolated mitral valve replacement at the Cardiovascular Surgery Clinic of Turkiye Yuksek Ihtisas Hospital. The overall hospital mortality rate was 8%. Postoperatively, all patients received 2.5 mg/day warfarin, and 225 mg/day dypridamole and 250 mg/day aspirin following removal of mediastinal tubes. This regimen was continued indefinitely thereafter. RESULTS: Postoperatively, the mean International Normalized Ratio (INR) was 1.4 +/- 0.67 (range: 0.9 to 4.19) and mean prothrombin time 13.33 +/- 1.98 min (range: 11.7 to 21.3 min). Mean follow up was 1.42 +/- 1.2 years (range: 2 months to 8.3 years); total cumulative follow up was 322.75 patient-years (pt-yr). During follow up, six patients (1.85% per pt-yr) developed thromboembolic complications (including mechanical valve thrombosis), two (0.62% per pt-yr) developed oral anticoagulant-related bleeding, and two (0.62% per pt-yr) developed paravalvular leak. Five patients died during follow up (late mortality rate 1.2% per pt-yr). The nine-year actuarial survival rate was 93.9 +/- 4.8% for the entire group. CONCLUSIONS: Low-dose oral anticoagulation after mitral valve replacement with St. Jude Medical prosthesis in elderly patients provided satisfactory clinical results.

Actuarial Analysis↗
PubMed1997

Septal myectomy in hypertrophic obstructive cardiomyopathy: late results with stress echocardiography.

BACKGROUND: This study was performed to assess the functional capacity of the survivors of septal myectomy for the treatment of hypertrophic obstructive cardiomyopathy in long-term follow-up as assessed by dobutamine stress echocardiography. METHODS: Sixty-nine patients with hypertrophic obstructive cardiomyopathy underwent septal myectomy between 1975 and 1996. The mean age was 25.4 +/- 13.6 years (range, 6-58 years), and 10 of the patients were women. The early mortality was 4.3%. Hospital survivors (95.7%) were followed up for a mean of 43.8 +/- 28.7 months (range, 6-114 months). RESULTS: The postoperative mean functional capacity of the group was 1.47 +/- 0.56. No late deaths were reported. Forty-nine patients (74.2%) were evaluated with standard echocardiographic techniques, and 29 (43.9%) patients underwent dobutamine stress echocardiography. There was a significant decrease in the thickness of the interventricular septum after surgery. The mean preoperative and postoperative septal thickness was 1.99 +/- 0.59 cm (range, 1.3-3.8 cm) and 1.55 +/- 0.41 cm (range, 0.96-2.8 cm), respectively (p < 0.004). The mean posterior wall thickness was significantly less than the preoperative value (p = 0.008) and the left ventricular end-diastolic diameter was slightly greater in the postoperative measurements, but the difference was not significant (p = 0.162). Postoperative left ventricular outflow systolic gradients were reduced significantly when compared with preoperative values (preoperative mean, 78.4 +/- 33.6 mm Hg, range, 50-212 mm Hg versus postoperative mean, 17.9 +/- 15.9 mm Hg: range, 0-40 mm Hg; p < 0.0001). CONCLUSION: Septal myectomy for patients with hypertrophic obstructive cardiomyopathy is a safe procedure with excellent clinical and functional results in the long-term follow-up.

Actuarial Analysis↗