Using oxidant and antioxidant levels to predict the duration of both acute peripheral and mesenteric ischemia.

OBJECTIVE: The aim of this study was to determine the relationship between oxidative stress markers and the duration of ischemia in rat mesenteric and peripheral ischemia models. METHODS: Forty rats were divided into five equal groups, as follows: rats in Group I (control group) were sacrificed to determine the baseline characteristics of the serum markers; the superior mesenteric artery was clamped via a simple laparotomy to induce mesenteric ischemia in Groups II and III; the right common femoral artery was clamped to induce peripheral ischemia in Groups IV and V. Blood samples were taken at 2 (Groups II and IV) and 6 (Groups III and V) hours after these procedures. The serum total oxidative status (TOS), total antioxidant capacity (TAC), oxidative stress index (OSI) and paraoxonase-1 (PON-1) enzyme activities were evaluated in the samples obtained from each group. RESULTS: The OSI level of the control group was 91.00±5.46 (mean ± SD). The OSI levels taken 2 hours after the induction of mesenteric ischemia and peripheral ischemia were significantly higher (194.50±11.16 and 301.75±19.98, respectively (p<0.05)). However, these levels decreased to 151.88±17.02 (mesenteric ischemia) and 108.88±9.46 (peripheral ischemia) after 6 hours. The PON-1 levels of Group III (mesenteric ischemia at 6 hours) (99.75±7.26), Group IV (peripheral ischemia at 2 hours) (96.88±4.09), and Group V (peripheral ischemia at 6 hours) (111.25±10.33) were slightly elevated over that of the control group (87.38±5.31). However, the PON-1 level of Group II (mesenteric ischemia at 2 hours) (42.88±3.14) was lower than that of the other groups (p<0.05). CONCLUSION: Despite the increment of oxidative markers in early periods of ischemia (2(nd) hour), which was a hypoxic response of ischemic cells, they have decreased markedly in prolonged ischemia. This might have been caused by the opening of some collateral circulation or the destruction of the ischemic cells.

Iloprost reduces myocardial edema in a rat model of myocardial ischemia reperfusion.

OBJECTIVE: Myocardial ischemia severely reduces myocyte longevity and function. Extensive interstitial edema and cell damage occur as a result of myocardial reperfusion injury. Current therapies are directed at prevention of ischemia-induced damage to cardiac tissue. Iloprost is a novel pharmaceutical agent for the treatment of ischemia. METHODS: Twenty rats were segregated into four experimental groups. The procedure control group consisted of four rats undergoing a sham operation. The remaining 16 rats were divided into two equal groups. The first group (control group) received a continuous intravenous infusion of physiological serum immediately prior to the procedure. Iloprost was administered by a continuous intravenous infusion into the right jugular vein at an infusion rate of 100 ng/kg/min for 30 minutes prior to reperfusion in the experimental group (study group). Following the infusion treatments, ligation of the left coronary artery was conducted for 30 minutes to induce myocardial ischemia. The rats were euthanized 24 hours after reperfusion and cardiac tissue was harvested from all specimens for analysis. RESULTS: Histological examination revealed three myocardial tissue specimens with grade II damage and five myocardial tissue specimens with grade III reperfusion injury in the control group. However, the study group consisted of two grade III myocardial tissue specimens, five grade II myocardial tissue specimens and one grade I myocardial tissue specimen. Moreover, a statistically significant reduction in myocardial edema was observed in the study group (p=0.022). CONCLUSION: Our results support the hypothesis that iloprost enhances protection against cardiac ischemia reperfusion injury. This protective effect may be associated with vasodilation, antioxidant or anti-edema mechanisms.

Serum ischaemia-modified albumin level is an irrelevant predictive factor for ischaemic duration in mesenteric ischaemia.

BACKGROUND: Acute mesenteric ischaemia is an emergency condition that requires urgent and expeditious diagnosis and immediate surgical or medical intervention. The initial hours are critical for the recovery of the affected bowel segment. Thus, its clinic diagnostic biomarkers are important when it comes to reducing mortality and morbidity rates. METHODS: Twenty-four male Sprague-Dawley rats were included in the study. The rats were divided into three equal groups. Those in Group I were sacrificed to determine the basal serum values of ischaemia-modified albumin (IMA) after a simple laparotomy. The superior mesenteric artery (SMA) was clamped in a simple laparotomy in Groups II and III; blood samples were taken at 120 minutes in Group II and 360 minutes in Group III. The serum IMA levels were identified from the blood samples and the results obtained were compared statistically. RESULTS: The serum IMA levels were determined to be 22±6 (22) µ/L, 34±7 (34) µ/L and 36±4 (37) µ/L in Groups I, II and III, respectively. The differences between the groups were not statistically significant. CONCLUSION: Our results showed that the serum IMA level is not an appropriate biomarker for acute mesenteric ischaemia. Additionally, the IMA level is not an appropriate biomarker for the detection of ischaemia duration. However, future studies should be conducted to clarify the efficacy of serum IMA levels under different ischaemic conditions.

Low dose anticoagulation after St. Jude Medical prosthesis implantation in patients under 18 years of age.

Between September 1986 and January 1994, 129 St. Jude Medical prostheses were implanted in 113 patients who were 18-year-old or younger at the Cardiovascular Surgery Clinic of Turkiye Yuksek Ihtisas Hospital. Thirty-seven patients underwent aortic, 60 patients mitral and the remaining 16 patients double valve replacement. Overall hospital mortality was 7.9% (9/113). All patients received 2.5 mg/day warfarin from the first postoperative day, in addition 225 mg/day dipyridamole and 100 mg/day aspirin was given following the removal of mediastinal tubes. This regimen was continued indefinitely thereafter. Follow up period ranged between 2-94 months. Total follow up experience was 276.4 patient-years. There were five late deaths; the cause of death was prosthetic valve thrombosis in two patients, intracerebral hemorrhage in one, cardiomyopathy in one, and sudden death in one. Other late complications included one endocarditis, a further anticoagulant related bleeding and one paravalvular leak. There was no case of cerebral or peripheral embolism reported. Seven-year actuarial survival was 92.4 +/- 6.8% for the entire group, 84.6 +/- 13.8% after mitral and 100% after aortic or double valve replacement. In conclusion, low dose oral anticoagulation after heart valve replacement with St. Jude Medical prosthesis in this age group showed satisfactory clinical results.

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.

Treatment of functional tricuspid regurgitation by bicuspidalization annuloplasty during mitral valve surgery.

BACKGROUND AND AIMS OF THE STUDY: Surgical treatment of functional tricuspid regurgitation associated with advanced valvular disease remains controversial, mainly due to the difficulty in choosing between valve replacement or reconstructive surgery. Failure to correct tricuspid regurgitation during valvular surgery carries a poor prognosis, as reoperation may represent a significant risk to the patient. Thus correct tricuspid valve surgery is vital to achieve improved early and long-term clinical results. METHODS: A total of 142 patients underwent concomitant tricuspid annuloplasty with mitral valve replacement and their clinical outcome was assessed. RESULTS: Overall hospital mortality rate was 11.3%. Seven patients died during follow up. The overall actuarial survival rate for 10 years was 74.1 +/- 14.2%. Postoperatively, 75.8% of the patients had no residual tricuspid insufficiency, while 24.2% had first- or second-degree tricuspid insufficiency and were treated medically. All patients were in NHYA functional class I or II postoperatively. CONCLUSION: Clinically, it is important to assess the severity of functional tricuspid insufficiency before and/or during the operation. Bicuspidalization annuloplasty for functional tricuspid insufficiency has provided good results, with a low incidence of reoperation and significant clinical improvement. The technique could be used in most patients with functional tricuspid regurgitation.

Late results of mitral valve replacement with Carpentier-Edwards high profile bioprosthesis in young adults.

Carpentier-Edwards (C/E) high profile supra-annular porcine bioprostheses were implanted in 163 patients between September 1982-February 1987 in the mitral position due to rheumatic disease. The patients' ages ranged between 15 and 58 years (mean: 36.5 +/- 11.5). One hundred-two of the patients (62.5%) were female. The hospital mortality was 9.8% (16/163). The total cumulative follow-up period was 1093 patient-years (p-y) with a mean of 7.3 +/- 3.5 p-y (range 6 months-12 years). Linearised occurrence rates of the late complications were as follows: Thromboembolism 0.82%/p-v, anticoagulant-related bleeding 1.0%/p-y, prosthetic valve endocarditis 0.09%/p-y. Actuarial survival rates for 5 and 12 years were 87% +/- 6% and 76% +/- 9%, respectively, with 95% confidence limits. Freedom from structural deterioration was 92% +/- 5% for 5 years and 44% +/- 11% for 12 years. Freedom from all valve-related complications was 81% +/- 7 for 5 years and 26% +/- 9 for 12 years. In conclusion, this prosthesis provides satisfactory clinical performance in young population despite the high risk of degeneration with good prognosis and better tolerability of reoperation.

Comparison of 21-23 size St. Jude medical valves to the 27-29 size mechanical valves in aortic position. Ten-year follow-up.

BACKGROUND: Between 1986 and 1996, 194 patients underwent isolated aortic valve replacement with 21-23 no. St. Jude Medical mechanical heart valves (small sized group) and 163 patients with 27-29 no. (large sized group). METHODS: The mean age at operation was 45.04+/-15.90 years (range: 12-76 years) for the small sized group and 38.05+/-13.41 years (range: 16-68 years) for the large sized group. Preoperatively, 39.7% of the patients from the small sized group and 42.9% from the large sized group had pure aortic stenosis, 31.9% and 27.6% had pure aortic insufficiency. Most of the patients had rheumatic valve disease. RESULTS: The overall hospital mortality rate was 12.4% and 3.07% respectively in the small sized and large sized groups (p<0.001). The overall actuarial survival rate for 10 years was 95.33+/-2.73% and 93.06+/-3.98% respectively in the small sized group and large sized group (p>0.05). In the small sized group male sex and all complications, in large sized group age and all complications were the statistically important hospital mortality predictors (p<0.05). CONCLUSIONS: Although, operative mortality and long term morbidity were higher in the small sized group, these changes did not reflect the actuarial survivals between the groups. Small sized valves carry some risk, but these risks do not affect long-term survival.

Hemodynamic effects of acute intestinal ischemia.

Twelve animals entered in this study with the aim of documenting that superior mesenteric artery small occlusions lasting for one hour have adverse effects on the myocardium. Three hours after cross clamp removal CO decreased to 1.07 +/- 0.11 from 1.99-0.09 a preoperative value (p < 0.01) and PCWP increased to 17 +/- 3 from 8 +/- 3 a preoperative value. MOE reduced to 40-5% 3 hours after cross clamp removal. MLE was -0.21 +/- 0.11 three hours after clamp removal. Changes in MOE and MLE were commented as a defect in myocardial aerobic metabolism. As a result of this study it was concluded that toxic mediators are released from the intestine being reperfused after temporary occlusions of the SMA impair myocardial metabolism, resulting in decreased hemodynamic functions.

Surgical approach to pseudoaneurysms with Behçet's disease.

One of the arterial complications of Behçet's disease, arterial false aneurysms, has a sudden onset of symptoms and high mortality risk if left untreated. Four cases with arterial pseudoaneurysms of 3 male patients is reported and the choice of surgical intervention is emphasized. It is underlined that PTFE grafts are the graft of choice in reconstructions for arterial complications of Behçet's disease.

The beneficial effects of aminophylline administration on heparin reversal with protamine.

The aim of this study was to demonstrate the beneficial effects of aminophylline on protamine cardiotoxicity. Thirty-four patients were examined, 17 of whom received aminophylline 3 mg/kg before protamine administration, being the study group, while the other 17, being the control group, did not. All cardiac output and biochemical measurements were evaluated 5 min following protamine administration. The cAMP level was 43.4 +/- 3.51 pmol/ml in the study group and 18.7 +/- 2.98 in the control group (P < 0.0001) before protamine administration, while the oxygen extraction rate decreased from 49% to 44 +/- 2% in the control group, and from 51.2% to 47 +/- 3% in the study group (P < 0.03). The N-acetyl glucosaminidase value was 16.9 +/- 13.9 pmol/ml in the study group and 27.8 +/- 1.47 pmol/ml in the control group (P < 0.01), and myocardial lactate extraction was -0.20 +/- 0.03 in the control group and -0.07 +/- 0.07 in the study group (P < 0.001). The left ventricular stroke work index was 28.6 +/- 3.14 gm/m2 in the control group and 37 +/- 6.77 gm/m2 in the study group (P < 0.002). The findings of this study led us to conclude that the adverse effects of heparin neutralization using protamine can be relieved by aminophylline.

Results of right coronary artery endarterectomy with or without patchplasty.

We report preoperative and early postoperative findings of 286 coronary bypass patients operated between 1988 and 1998 who had endarterectomy and/or patchplasty to the right coronary artery. In this retrospective study there were 61 cases with only saphenous vein patchplasty to the right coronary artery (patch group), 57 patients who underwent endarterectomy and patchplasty (open-patch group), and 229 patients having closed endarterectomy to the right coronary artery (closed group). A group of 150 patients having a saphenous vein graft to the right coronary artery without endarterectomy were chosen as a control group. Gender, age, family history, smoking history, diabetes, hyperlipidemia, hypertension, nature of the angina, severity of the coronary artery disease, left ventricular functions, preoperative rhythm, and electrocardiographic patterns were evaluated for their effect on early mortality among groups. No significant difference was detected. Positive inotropic and mechanical support need was higher in the closed group at the end of the operation and in the intensive care unit. Duration of cardiopulmonary bypass and clamp time was higher in the open-patch group. Atrial fibrillation in the early postoperative period was more frequent in the patch and closed groups. Complete atrioventricular block development and the need for a pacemaker were higher in the open-patch and closed groups. Non-Q wave myocardial infarction was more frequent in the closed group. Mortality rates were higher in the open-patch and closed groups. We conclude that endarterectomy to right coronary artery should be avoided if possible, and patchplasty with saphenous vein should be preferred.

Aortic valve replacement with the St. Jude Medical prosthesis and fixed dose anticoagulation.

Over a 10-year period, between 1986 and 1996, 865 patients underwent primary aortic valve replacement (AVR) with the St. Jude Medical mechanical prosthesis. Patients who had undergone valve replacement with a different type of prosthesis previously were excluded from this study. Patient age ranged from 11 to 79 years. The mean age was 42.9 +/- 14.54. The gender distribution was 396 men (45.8%) and 469 women (54.2%). All patients received 2.5 mg/day Coumadin after extubation. A combination of the antiaggregant therapy (Dypridamole 3X 75 mg/day, Asprine 100 mg/day) was added after removal of the chest tubes. The dosage of Coumadin was maintained constant regardless of the prothrombin time (PT) or cardiac rhythm. There were 101 valve-related complications (4.2% per patient year [ppy]) occurring in the late follow-up period. Of these complications; 38 were anticoagulant-related hemorrhage (1.58% ppy), 3 were paravalvular leak (0.12% ppy), and 36 were thromboembolism (1.4% ppy). There were 24 reoperations (0.99% ppy) and 17 late deaths. The linearized late mortality rate was 0.7% ppy. Long-term survival estimates at 5 and 10 years were 97.14 +/- 0.82% and 94.86 +/- 1.54%, respectively. We conclude from the data that the St. Jude Medical valve may allow the use of a low level of anticoagulation. This study shows that fixed dose oral anticoagulation does not increase the rate of thromboembolism in patients with the St. Jude aortic valve. This protocol does not result in reduction of bleeding complications, however.