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Biomedical subjects

M A Ergin

Publications and source records attributed to M A Ergin.

At least 19 recordsLinked to original sources
PubMed1995

Surgical techniques in prosthetic valve endocarditis.

Annular extension of the infectious process is common in prosthetic valve endocarditis and carries a substantial prognostic significance in determining the immediate and late results of the surgical treatment of prosthetic valve endocarditis. Advanced destruction of the annular tissues requires complex reparative techniques for treatment. The cardiac surgeon faces the challenge of removing all infected tissues while preserving and restoring the functional integrity of the ventricular inlet and outlet. Familiarity with a growing number of specialized techniques is necessary for effective surgical treatment of these destructive lesions. This article is a synopsis of surgical techniques that we have found useful in the treatment of extensive annular destruction in bacterial endocarditis.

Endocarditis, Bacterial↗
PubMed1994

Significance of distal false lumen after type A dissection repair.

Fifty-eight patients underwent repair of acute type A dissection between 1986 and 1992. Follow-up aortogram, computed tomographic scan with contrast, magnetic resonance imaging scan, or a combination of these tests was available in 38 patients with preoperatively patent distal false lumens. All distal anastomoses were constructed with the open technique during a period of circulatory arrest. There were 25 suture and 13 intraluminal graft anastomoses. Patency of the distal false lumen was found in 47.3%. Use of the intraluminal graft for the distal anastomosis decreased patency, although not significantly (4/13, 30% versus 14/25, 56%; p = 0.14). The direction of flow into the false lumen was antegrade in 11 of 24 (45.8%) of sutured anastomoses and 0 of 9 intraluminal graft anastomoses (p < 0.01). Actuarial survival at 5 years for patients with closed distal false lumen was 95% +/- 4.8% versus 76% +/- 15% for patients with patency of the distal false lumen (p = not significant). Event-free survival at 5 years for both groups was 84% +/- 8.3% (closed false lumen) and 63% +/- 13.5% (patency of distal false lumen; p = not significant). This experience indicates that in the treatment of acute type A dissections, operative strategy and anastomotic technique play a role in reducing the incidence of patency and related complications of the distal false lumen.

Actuarial Analysis↗
PubMed1994

Pathogenesis of spinal cord injury during simulated aneurysm repair in a chronic animal model.

The pathogenesis of paraplegia after repair of thoracic aortic aneurysms is controversial. Using direct spinal cord evoked potential monitoring, critical intercostal arteries (CICA) were identified to evaluate the impact of backbleeding and ligation versus that of preservation during simulated aneurysm repair. Thirty pigs (40 kg) were randomly assigned to one of five groups. In groups 1 through 4, a thoracic segment containing CICA was cross-clamped for 60 minutes and distal aortic perfusion was provided by a centrifugal pump. In groups 1 and 2, the thoracic segment was vented, maintaining segment pressure at 0 mm Hg; CICA were ligated in group 1 and preserved in group 2. Thoracic segment was perfused at 70 mm Hg in groups 3 and 4; CICA were ligated in group 3 and preserved in group 4. Critical intercostal artery ligations were performed at the end of the cross-clamp period. In group 5 simple cross-clamping at the left subclavian artery was performed as a control. The combination of venting and ligation of CICA correlated with impaired neurologic outcome according to Tarlov's score (median, 1.5 in group 1 versus 3 in group 2; p = 0.015), indicated by a significant difference in median values of direct spinal cord evoked potential amplitude (expressed as a fraction of baseline values) at 120 minutes after cross-clamping (0.76 in group 1 versus 0.98 in group 2; p = 0.0082).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Hypothermic circulatory arrest and other methods of cerebral protection during operations on the thoracic aorta.

Current surgical techniques in operations on the thoracic aorta frequently require exclusion of the cerebral circulation for varying periods. During these periods, hypothermic circulatory arrest (HCA), selective cerebral perfusion (SCP), and retrograde cerebral perfusion (RCP) can be used for cerebral protection. Hypothermia is the principle component of these methods of protection. The main protective effect of hypothermia is based on reduction of cerebral energy expenditures and largely depends on adequate suppression of cerebral function. It is most effective at deep hypothermic levels (13 degrees C to 15 degrees C). Measures that preserve autoregulation of cerebral blood flow help increase the margin of safety with all methods of protection. There is solid experimental and clinical data indicating the safe limits and outcome following HCA. Current applications of SCP and RCP are fairly recent developments and do not have comparable supporting data. SCP can be used without deep hypothermia and allows prolonged periods of cerebral protection, but is complex in application. RCP is simpler, but always requires deep hypothermia. Present clinical data do not allow separation of its protective effect from that of HCA alone. Recent modifications in the application of HCA include monitoring of cerebral O2 extraction, and selective use of supplemental SCP to limit arrest times to less than 50 minutes, or RCP to prevent embolic strokes, as indicated. These changes appear to have reduced the overall mortality, the severity of embolic strokes, and stroke-related mortality.

Adult↗
PubMed1994

Comparison of retrograde cerebral perfusion to antegrade cerebral perfusion and hypothermic circulatory arrest in a chronic porcine model.

Retrograde cerebral perfusion (RCP) is a new method of cerebral protection that has been touted as an improvement over hypothermic circulatory arrest (HCA). However, RCP has been used clinically for durations and at temperatures that are "safe" for HCA alone. This study was designed to compare RCP to HCA and antegrade cerebral perfusion (ACP) deliberately exceeding "safe" limits, in order to determine unequivocally whether RCP provides better cerebral protection than HCA. Four groups of six Yorkshire pigs (20 to 30 kg) were randomly assigned to undergo 90 minutes of RCP, ACP, HCA, or HCA with heads packed in ice (HCA-HP) at an esophageal temperature of 20 degrees C. Arterial, mixed venous and cerebral venous oxygen, glucose and lactate contents; quantitative EEG; were monitored at baseline (37 degrees C); at the end of cooling cardiopulmonary bypass (20 degrees C); during rewarming (30 degrees C); and at two and four hours post intervention. Animals were recovered and were evaluated daily using a quantitative behavioral score (0 to 9). Mean behavioral score was lower in the HCA group than in the other three groups at seven days (HCA 5.8 +/- 1.1; RCP 8.5 +/- 0.2; ACP 9.0 +/- 0.0; HCA-HP 8.5 +/- 0.2, p < 0.05). Recovery of QEEG was better in the ACP group than in all others, but the RCP group had faster EEG recovery than HCA alone, although not better than HCA-HP (HCA 15 +/- 4; RCP 27 +/- 3; ACP 78 +/- 5; HCA-HP 19 +/- 3, p < 0.001). However, histopathological evidence of ischemic injury was present in 5 of 6 HCA animals and also in 4 of 6 of the HCP-HP group, but only in 1 of 6 RCP animals and in none of the ACP group. This study demonstrates that ACP affords the best cerebral protection by all outcome measures, but RCP provides clear improvement compared to HCA.

Animals↗
PubMed1994

A new technique using somatosensory evoked potential guidance during descending and thoracoabdominal aortic repairs.

Recent work in our laboratory has demonstrated the effectiveness of somatosensory evoked potentials (SEPs) in identifying the critical intercostal arteries (CICAs) for preserving spinal cord integrity during simulated aortic aneurysm repairs in the pig. Further studies have also demonstrated increased preservation of neurological function during prolonged aortic clamping if CICAs are perfused until ligation or clipping, as opposed to transaortic identification of back-bleeding intercostals and their subsequent ligation. We have developed a technique of repair of descending thoracic and thoracoabdominal aortic aneurysms and dissections that uses these principles. Since January 1993, 26 patients have undergone repair of their aortas using this new technique and SEP directed intercostal artery ablation. There were 22 (85%) long-term survivors among 10 thoracoabdominal and 16 descending aortic repairs. All patients with uncorrected abnormal SEP recordings developed paralysis; one patient who required reimplantation of an intercostal artery island into the aortic graft had normal neurological function postoperatively. Paraplegia was seen in only one of the surviving patients, but this patient had normal intra- and postoperative SEPs (4% false negative). Our experience suggests that SEP-guided obliteration of intercostal arteries while maintaining perfusion may be a useful approach to the surgical repair of descending and thoracoabdominal aortic disease.

Adolescent↗
PubMed1994

Subtypes of acute aortic dissection.

The technique of open distal anastomosis using deep hypothermic circulatory arrest was used in 69 cases of acute type A aortic dissection. These cases were subcategorized by site of intimal tear, which was found in the ascending aorta in 41 patients (60%), in the arch in 22 patients (32%), and in the descending aorta in 5 patients (7%). Clinical characteristics and complications are described for these subtypes. Hospital mortality, which was 14.5% overall for acute type A dissections, was 14.6% for ascending tears, 18.2% for arch tears, and 0% for descending aortic tears. Six-year survival was 69% +/- 15% for ascending tears, 69% +/- 22% for arch tears, and 80% +/- 25% for descending tears (mean +/- SEM, p = NS). A classification system for aortic dissection is proposed, based on both site of origin and propagation.

Acute Disease↗
PubMed1994

Hypothermic circulatory arrest in operations on the thoracic aorta. Determinants of operative mortality and neurologic outcome.

This study was undertaken to determine the factors that influence the final outcome after hypothermic circulatory arrest. Between 1985 and 1992 a uniform method of hypothermic circulatory arrest was used in 200 patients as the primary method of cerebral protection during operations on aneurysms of the thoracic aorta. There were 30 hospital deaths (15%). Age greater than 60 years (relative risk 3.7, p < 0.02), emergency operation and hemodynamic compromise (relative risk 22.2, p < 0.000), concomitant procedures (relative risk 2.7, p < 0.04), presentation with new neurologic symptoms (relative risk 5.2, p < 0.04), and postoperative permanent neurologic deficits (relative risk 9.4, p < 0.000) were found to be significant predictors of operative mortality. A total of 183 patients were available for evaluation of neurologic function and outcome. Multivariate analysis of this cohort of patients by multiple logistic regression showed that temporary neurologic dysfunction occurred in 36 cases (19%). Temporary neurologic dysfunction correlated with the duration of hypothermic circulatory arrest (47 +/- 16 minutes; odds ratio 1.06/minute; p < 0.001) and age (66 +/- 14 years; odds ratio 1.07/year; p < 0.001). Embolic strokes occurred in 22 patients (11%) and were associated with permanent deficits in 13 (7%). Strokes correlated significantly with age (older than 60, 21% versus younger than 60, 1%; p < 0.001) and operations on the arch and descending aortic aneurysms containing clot or atheroma (p < 0.001). This experience shows that the operative mortality is not affected by any parameters related to the use of hypothermic circulatory arrest. The incidence of temporary neurologic dysfunction rises linearly in relation to the age of the patient and the duration of hypothermic circulatory arrest. However, permanent neurologic injury is a result of thromboembolic events and is not related to the method of cerebral protection used. Additional methods to prevent perioperative embolic strokes are needed. Hypothermic circulatory arrest affords adequate cerebral protection if the arrest period is kept less than 60 minutes. We will continue to use this modality until the safety and utility of the alternate methods of cerebral protection are shown to be superior.

Aortic Dissection↗
PubMed1993

Coronary bypass with ejection fraction of 0.20 or less using centigrade cardioplegia: long-term follow-up.

Forty-two patients with an ejection fraction of 0.20 or less underwent coronary artery bypass grafting from 1986 to 1990 using a method of myocardial protection we term "centigrade cardioplegia," combining single-dose, cold, crystalloid cardioplegia, systemic hypothermia, and local hypothermia. Thirty-day mortality was 4.8% (2/42). Perioperative morbidity included two myocardial infarctions (4.8%) and one stroke (2.4%), which fully resolved. Postoperative left ventricular function improved (left ventricular ejection fraction, 0.157 +/- 0.028 to 0.226 +/- 0.085; p < 0.0002), as did New York Heart Association class (3.4 +/- 0.73 to 1.8 +/- 0.63; p < 0.0001) and Canadian class (3.3 +/- 0.81 to 0.61 +/- 0.92). Survival, 88% at 1 year, declined to 68% at 3 years and 34% at 6 years. This high-risk group had very acceptable short-term results, indicating adequate intraoperative myocardial protection. Four clinical variables were associated with long-term survival: (1) chief complaint of pain only (p = 0.05), (2) history of unstable angina (p = 0.04), (3) Canadian class less than IV (p = 0.05), and (4) New York Heart Association class less than IV (p = 0.05). Reduced survival, although not statistically significant (p = 0.07), was noted for right ventricular ejection fraction of 0.30 or less. These factors may help predict which patients with severe left ventricular dysfunction will benefit from revascularization.

Angina Pectoris↗
PubMed1992

Macromastia as a factor in sternal wound dehiscence following cardiac surgery: management combining chest wall reconstruction and reduction mammoplasty.

Major sternal wound infection occurs in nearly 2% of patients following coronary artery bypass graft surgery. The relationship of this complication to gender has not been reported in detail, nor has female breast size previously been implicated as a factor increasing the risk of sternotomy dehiscence. We report two cases of sternotomy wound dehiscence in women with large, pendulous breasts undergoing myocardial revascularization surgery and postulate that the weight of large, unsupported breasts produced inferolateral tension on the midline sternotomy incisions, contributing to dehiscence of the wounds. Chest wall reconstruction was accomplished using pectoralis muscle flaps, and the procedures were combined with amputative reduction of the size of the breasts, with subsequently successful healing in each case. Combining sternal reconstruction with breast reduction surgery may lead to improved secondary outcome, and postoperative use of supportive brassieres may reduce the frequency of this complication.

Aged↗