Ilhan Golbasi

Aortoiliac Kissing Stents: Long-term Results and Analysis of Risk Factors Affecting Patency

Purpose: To present the early and long-term results of aortoiliac kissing stents implantation and evaluate the risk factors affecting patency. Methods: The data were retrospectively reviewed on 68 patients (64 men; mean age 55±11, range 32–77) who underwent kissing stents implantation during a 12-year period. The majority of patients (64, 94%) had claudication; 4 patients had rest pain. All were smokers. There were bilateral or unilateral stenoses in 42 (62%) patients, and unilateral occlusion and contralateral stenosis in 26 (38%). Lesions were treated with simultaneous implantation of self-expanding (n=52) or balloon-expandable (n=16) stents. After the procedure, patency was determined with Doppler ultrasonography or angiography at 1, 3, 6, and 12 months and annually thereafter. Primary, assisted primary, and secondary patency rates were calculated with Kaplan-Meier analysis on an intention-to-treat basis, and risk factors affecting the patency rates were determined with the Cox regression analysis. Results: All procedures were technically and clinically successful. Complications occurred in 12%, but none required surgery. The follow-up period was 35±31 months. Primary, assisted primary, and secondary patency rates, respectively, were 76%, 90%, and 94% at 1 year; 63%, 86%, and 92% at 3 years; and 63%, 64%, and 81% at 5 years. In multivariate analysis, age <50 years and presence of iliac occlusion were identified as risk factors for reduced primary and assisted primary patency; a crossed configuration of kissing stents was identified as a risk factor for reduced primary patency. Conclusion: Implantation of kissing stents is a safe and effective alternative in the treatment of aortoiliac obstructions. However, overall primary and assisted primary patency rates are inferior to those reported for surgery. Long-term patency comparable to surgery may be obtained in patients >50 years and in those without an iliac occlusion, particularly if a favorable stent configuration is achieved.

Comparison of the vasodilatory effect of nadroparin, enoxaparin, dalteparin, and unfractioned heparin in human internal mammary artery.

The aim of this study was to investigate whether the low-molecular-weight heparins (LMWHs) (eg, nadroparin, enoxaparin, and dalteparin) cause a vasodilatory effect in human internal mammary artery (IMA) and to further compare its effect with unfractioned heparin (UFH). Samples of redundant IMA obtained from 20 patients undergoing a coronary artery bypass graft surgery were cut into 3-mm-wide rings and suspended in 20-mL organ baths. Isometric tension was continuously measured with an isometric force transducer connected to a computer-based data acquisition system. LMWHs (0.5-6 U/mL) caused a concentration-dependent relaxation in the endothelium-intact human IMA rings, which were precontracted with Phe (10−6 M) (P < 0.05). The vasodilator potency of LMWHs seems to be nearly similar while the maximal effect produced by LMWHs was less pronounced compared with that produced by UFH. Removal of endothelium totally abolished the responses of human IMA to LMWHs as well as UFH (P < 0.05). LMWHs-induced vasodilator effect was significantly attenuated by Nω-nitro-L-arginine methyl ester (L-NAME, 10−4 M) but not indomethacin (10−5 M). Our results have shown that LMWHs cause a dose-dependent relaxation in human IMA but are less effective than that produced by UFH. The vasorelaxant effects induced by each of LMWH are nearly similar and seem to be via endothelium-dependent mechanisms, including generation of nitric oxide.

Unfractioned heparin produces vasodilatory action on human internal mammary artery by endothelium-dependent mechanisms

The aim of this study was to investigate whether unfractioned heparin produces a direct vasodilatory effect on the human internal mammary artery (IMA) and the possible underlying mechanisms. Samples of redundant IMA were obtained from 20 patients undergoing coronary artery bypass graft surgery, and concentration-response curves to unfractioned heparin were constructed. Unfractioned heparin (0.5-6 U/mL) caused a concentration-dependent relaxation in the endothelium-intact human IMA rings precontracted with phenylephrine (10−6 M). Removal of endothelium significantly inhibited the responses of human IMA to unfractioned heparin (P < 0.05). Nω-Nitro-L-arginine methyl ester (L-NAME, 10−4 M), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10−5 M) and L-NAME (10−4 M) plus ODQ (10−5 M) partially reduced unfractioned heparin-induced vasodilatory response in endothelium-intact rings, whereas indomethacin alone had no effect. The vasodilatory effect of unfractioned heparin was completely inhibited by 40 mM KCl in the presence of L-NAME, ODQ, and indomethacin. These results clearly demonstrated that unfractioned heparin causes a concentration-dependent vasodilatation in human internal mammary artery, and this action seems to be via endothelium-dependent mechanisms, including generation of nitric oxide and endothelium-derived hyperpolarizing factor.

The inhibitory action of protamine on human internal thoracic artery contractions: the effect of free hemoglobin

OBJECTIVE We investigated the mechanism of the protamine action and the effects of free hemoglobin on protamine-induced responses in endothelium-denuded and-intact human internal thoracic artery (ITA) rings precontracted with phenylephrine (PE) or high KCl. METHODS Samples of redundant ITA obtained from patients undergoing a coronary artery bypass graft surgery were cut into 3 mm wide rings and suspended in 20 ml organ baths. Isometric tension was continuously measured with an isometric force transducer connected to a computer-based data acquisition system. RESULTS Acetylcholine (Ach, 10(-8)-10(-5) M) caused a concentration-dependent relaxation of PE-precontracted ITA rings. Free hemoglobin (0.1 and 0.5 microM) produced a concentration-dependent and significant decrease in sensitivity (pD(2)) and maximal contractility (E(max)) in response to Ach in PE-precontracted ITA rings (P<0.0001). Protamine (50-800 microg/ml), free hemoglobin (0.1 and 0.5 microM), nitric oxide (NO) blocker N(omega)-nitro-L-arginine methyl ester (L-NAME, 100 microM) or soluble guanylate cyclase inhibitor methylene blue (10 microM) administration did not cause a significant alteration on basal tonus of endothelium-intact or -denuded ITA rings. Protamine (50-800 microg/ml) induced concentration-dependent relaxation responses in ITA rings precontracted by either PE or high KCl. There was no difference in sensitivity or maximal response to protamine between the endothelium-intact and -denuded rings. Incubation of endothelium-intact or -denuded ITA rings with L-NAME or free hemoglobin or methylene blue did not cause a significant inhibition on relaxation responses to protamine. ITA ring contractions induced by stepwise addition of calcium to high KCl solution with no calcium were almost completely inhibited by protamine (P<0.0001). CONCLUSIONS It was suggested that protamine induced relaxation responses in human ITA rings is not NO- or endothelium-dependent but seems to depend on the interactions of protamine with calcium influxes and/or calcium release from intracellular stores in this tissue.

The effect of pentoxifylline on haemolysis during cardiopulmonary bypass in open-heart surgery.

Objective — Haemolysis has long been recognized as one of the responses to cardiopulmonary bypass (CPB). Pentoxifylline (PTX), a methylxanthine derivative, has been known for many years for its haemorrheological properties. In this prospective, randomized study, we investigated whether a PTX treatment would reduce the haemolysis during CPB. Methods — The effect of PTX treatment on haemolysis during CPB was studied in 25 patients (PTX group). Oral PTX (1200 mg/day in 3 divided doses) treatment for 3 days was followed by 300 mg i.v. PTX administration after anaesthesia induction.The control group consisted of 25 patients with equivalent surgery but no PTX treatment. Blood samples were collected at seven time points: prior to CPB, at 5 and 10 min of CPB and 5, 10 and 15 min after removal of cross clamping and 10 min after weaning from bypass in order to measure the haemolysis parameters, which included free haemoglobin and haptoglobin. Results — PTX-treatment caused statistically significant decrements in plasma free haemoglobin levels during CPB. On the other hand, plasma haptoglobin levels stayed higher in PTX-medicated patients during the CPB as compared to control subjects. Conclusions — These findings suggested that PTX may be an effective agent in reducing the haemolysis during CPB.

The effect of pentoxifylline on haemolysis in patients with double cardiac prosthetic valves

Objective — Intravascular haemolysis frequently occurs in patients with mechanical heart valve prostheses. In this prospective study, we investigated whether pentoxifylline (PTX) has an effect on haemolysis following prosthetic valvular replacement in 40 patients who underwent double valve (mitral and aortic) replacement. Methods and results — The patients were randomly assigned to two groups as control (n = 20) and PTX group (n = 20). PTX was given in a daily oral dose of 1200 mg (3 times 400 mg) for 120 days. Laboratory tests for evidence of haemolysis namely, haemoglobin (Hb), haematocrit (Hct), plasma total bilirubin, indirect bilirubin and haptoglobin levels, corrected reticulocyte percent and serum lactic dehydrogenase activity (SLDH) were performed before and after the PTX treatment. PTX treatment caused significant increases in Hb, Htc, and haptoglobin levels (P < 0.05, P<0.05 and P<0.01, respectively).Additionally, there were significant decreases in SLDH, total and indirect bilirubin levels, and corrected reticulocyte percent in patients receiving PTX as compared with their respective control values (P<0.01, for all). PTX treatment caused a significant improvement, to different extents, in signs of haemolysis in 60% of the patients. On the other hand, the response rate was 5% in the placebo-treated control group (P<0.05). Conclusions — These findings suggest that PTX may be an effective agent in the management of haemolysis in patients with prosthetic heart valves.

A single coronary artery from the right sinus of valsalva associated with atherosclerosis.

Anomalous origin of the main coronary arteries from the aorta is rare.We report a case with a single coronary artery from the right sinus of Valsalva associated with atherosclerosis. The patient was treated with a coronary artery bypass procedure: left internal mammary artery (LIMA) to the left anterior descending artery (LAD), right internal mammary artery (RIMA) to the right coronary artery (RCA).The postoperative course was uneventful.

The role of nitric oxide and potassium channels in the effect of adrenomedullin in human internal thoracic arteries.

We investigated the effects of adrenomedullin (ADM) and the role(s) of cyclooxygenase, nitric oxide (NO) synthase and potassium channels in the effects of ADM in human internal thoracic artery (ITA) rings. Samples of redundant ITA rings were suspended in organ baths and isometric tension was continuously recorded. ADM (10(-10)-10(-7)M) produced concentration-dependent relaxation responses in ITA rings precontracted by phenylephrine. The relaxant responses to ADM were significantly higher in endothelium-intact than denuded preparations. Incubation of ITA rings with indomethacin (10(-5)M) did not cause a significant decrease in relaxant responses to ADM, while 10(-4)M of N(omega)-nitro-L-arginine methyl ester caused a significant decrease. Both specific guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (5x10(-5)M) and ADM receptor antagonist ADM((22-52)) (10(-7)M) also caused significant decreases in relaxant responses to ADM. Neither 4-aminopyridine (5mM) nor glibenclamide (10(-5)M) caused significant alterations in vasodilatory effect of ADM. ADM-induced relaxation was significantly blunted by both charybdotoxin and apamin. The present study provided pharmacological evidence about the functional relaxant effect of ADM in human ITA preparations. The findings suggested that both Ca(2+)-activated potassium channels and endothelium, through release of NO play a major role in ADM-induced relaxations in isolated human ITA preparations.

Effects of short-term exposure to homocysteine on vascular responsiveness of human internal mammary artery

Abstract: The aim of this study was to investigate the acute direct effects of homocysteine (Hcy) on the vascular responsiveness of human internal mammary artery (IMA) and to define the possible underlying mechanisms. The contractile response to both phenylephrine (Phe) (−36%) and KCl (−18%) was significantly reduced in arteries that were incubated with Hcy (10−4 M, 30 minutes), compared with controls (P < 0.05). Removal of endothelium did not significantly alter the responses of human IMA to Phe. Hcy (10−4 M) also caused a relaxation response in human IMA rings precontracted with Phe (10−6 M) and this effect was not inhibited by Nω-nitro-L-arginine methyl ester (L-NAME, 10−4 M), by l-NAME (10−4 M) + indomethacin (10−5 M), or by intimal rubbing. In addition, contractions induced by stepwise addition to calcium (Ca2+) to high KCl solution with no Ca2+ were significantly inhibited by Hcy incubation as well as contractions induced by Phe in the absence of extracellular Ca2+ (P < 0.05). On the other hand, Hcy (10−4 M, 30 minutes) did not significantly inhibit the relaxation responses to either acetylcholine (ACh) or sodium nitroprusside (SNP) (P > 0.05). These results demonstrated that short-term exposure to Hcy significantly decreased vascular responsiveness in human IMA without affecting endothelium-dependent and -independent vasorelaxation. This effect is not NO-, prostaglandin- or endothelium-dependent. The mechanism is uncertain but seems to depend on the interactions of Hcy with Ca2+ influxes and/or other undefined direct effects in this tissue.

Outcomes and Readmissions After Continuous Flow Left Ventricular Assist Device: Heartmate II Versus Heartware Ventricular Assist Device.

INTRODUCTION Donor organ shortage is still a problem for heart transplantation. Only 10% of patients in waiting list undergo heart transplantation. Over the last 5 years, 2 different continuous flow pumps, the HeartMate II and the HeartWare, have been successful clinically in the alternative treatment of patients with end-stage heart disease. METHODS Fifty-five patients underwent left ventricular assist device implantation between 2011 and 2014. Patients were followed on pump support for complications and intraoperative outcomes. Potential device-related complications include infections, bleeding liver dysfunction, renal dysfunction, right ventricular failure, stroke, thromboembolism, gastrointestinal bleeding, and wound infection. RESULTS The only preoperative significant difference between groups in the study was age; the Heartmate II group were significantly older than Heartware group. There were no differences in gender, body mass index, or body surface area. The Heartware has a better 1-year survival rate, although the difference was not significant. Patients with Heartmate II had a higher incidence of gastrointestinal bleeding and driveline infection. The Heartware group had a higher incidence of stroke and pump thrombosis. CONCLUSIONS The Heartmate II and Heartware are comparable in most respects such as survival, intraoperative features, and major complications.