Povilas Jakuška

Effects of intraoperative external head cooling on short-term cognitive function in patients after coronary artery bypass graft surgery

The aim of study was to assess the effects of an intraoperative external head-cooling technique on cognitive dysfunction in the early postoperative period (at the 10th day) in patients after coronary artery bypass graft (CABG) surgery. Patients in Group H (n=25) were cooled with CPB and the intraoperative, external head-cooling technique, patients in Group C (n=25) were cooled only with cardiopulmonary bypass (CPB) to achieve mild hypothermia (33 – 34°C). Cognitive function was analyzed before the operation and after the surgery using the Mini Mental State Examination (MMSE), the Modified Visual Reproduction Test from the Wechsler Memory Scale, Trail Making (A/B), WAIS - Digit Span (WDS) and WAIS Digit Symbol Substitution Test (WDSST). The incidence of cognitive impairment at the 10th day after the surgery was 36% (n=9) in Group H and 64% (n=16) in Group C (p=0.048). The temperature during the aortic cross-clamp period was associated with a lower rate of cognitive dysfunction (p=0.05, r2=0.09). The intraoperative, external head-cooling technique during the aortic cross-clamp period has a neuroprotective effect and leads to less short-term cognitive function impairment after CABG surgery.

Action of calcium antagonists and agonists on isolated human thoracic arteries used for coronary artery bypass grafting

BACKGROUND The goal of this study was to investigate the modulation of the contraction-relaxation effects in isolated human thoracic artery samples of three calcium-channel antagonists, amlodipine (CAS [88150-42-9]), cerebrocrast (CAS [118790-71-9]) and diltiazem (CAS [42399-41-7]), and two calcium-channel agonists, CGP 28392 (CAS [89289-93-0]) and benzimidazole derivative. To estimate the endothelial function of the artery samples, carbachol, an agonist of muscarinic receptors, was used. METHODS The experiments were conducted on isolated human thoracic artery samples, and their isometric contractions were recorded using an i-FOT10 force transducer. Cumulative concentration-contraction curves of the tested agents (10(-7) to 10(-4) M) were established. RESULTS Carbachol at concentrations of 10(-7) to 10(-6) M did not cause any relaxation of artery rings precontracted by 10(-4) M phenylephrine, and at concentrations of 10(-5) and 10(-4) M, isometric contractions increased by 7% and 20%, respectively. In response to amlodipine, cerebrocrast and CGP28392, the contraction of artery samples increased significantly, whereas diltiazem and benzimidazole derivative caused their relaxation by ≈55%. CONCLUSION The obtained data indicate that the endothelium of the thoracic artery, which is used for coronary artery bypass grafting, is damaged by and may have some influence on the inadequate response of 1,4-dihydropyrine type calcium-channel antagonists.

Effects of calcium antagonists and agonists on isolated human v. saphena magna used for coronary artery bypass grafting and guinea pig’s papillary muscle

BACKGROUND The goal of this study was to investigate the movement of contraction-relaxation effects on isolated human blood vessel samples by the actions of amlodipine (CAS 88150-42-9), cerebrocrast (CAS 118790-71-9), diltiazem (CAS 42399-41-7), and a benzimidazole derivative. Additionally, their effects on isometric contraction force and the duration of the action potential (AP) were measured. METHODS The experiments were carried out on isolated human v. saphena magna samples and papillary muscles of adult guinea pigs. Isometric contraction and the AP were recorded using a force transducer and standard microelectrode technique. RESULTS Phenylephrine (10(-4) M) caused contractions of vein rings to 928 +/- 76.5 mg. All the tested agents at a concentration of 10(-7)-10(-4) M significantly relaxed the smooth muscle in a dose-dependent manner. The weakest response was shown by amlodipine. Pre-treatment with 50 microM of amlodipine, diltiazem and benzimidazole for 30 min significantly increased the magnitude of the contraction induced by phenylephrine in concentration-dependent (10(-6)-10(-4) M) fashion but only in the benzimidazole group versus other tested agents and the control. The benzimidazole derivative caused augmentation of isometric contraction of the papillary muscles and negligible lengthening of AP duration; the other agents tested showed opposite effects. CONCLUSION These results show that agents possessing positive or negative inotropic action significantly relaxed the isolated vein samples precontracted with phenylephrine. These responses point to a different mechanism of action underlying both calcium antagonist and agonist effects even though their action ultimately resulted in vasodilatation.

Non-ischaemic mitral valve suture annuloplasty: late follow-up results

Objective: To evaluate late outcomes after posterior mitral valve (MV) annulus double-suture annuloplasty for degenerative (non-ischaemic) MV insufficiency. Design: Between 2005 and 2011, 138 patients underwent MV repair using posterior MV double-suture annuloplasty and an additional 105 patients underwent tricuspid valve repair. The study protocol included operative mortality, reoperation rate and reasons, as well as echocardiographic parameters at pre- and postoperative and follow-up periods (2-9 years). Results: In-hospital mortality was 2/138 (1.45%). Early post operation, no regurgitation was noted in 74/136 (54.4%) patients, Io regurgitation was observed in 55/136 (40.4%), IIo was observed in 6/136 (4.4%) and IIIo was observed in 1/136 (0.7%); during late follow-up (from 2 to 9 years), no regurgitation was observed in 21.6% patients, Io was observed in 58%, IIo was observed in 17% and IIIo was observed in 3.4%. The mean preoperative anterolateral diameter of the MV annulus was 39.02±4.97 mm and, at late follow-up, it was 27.66±3.94 mm (p=0.000); at these same time points, left ventricular end-diastolic diameter (LVEDD) was 55.74±7.29 mm and 49.17±6.01 mm (p=0.000), respectively, and the left ventricular ejection fraction (LVEF) was 53.08±8.93% and 50.92±6.78%, respectively (p=0.007). Conclusions: This study demonstrates suture annuloplasty to be an effective treatment up to 9 years for degenerative mitral valve disease. This technique enables preservation of the posterior mitral valve annulus diameter with stable long-term (up to 9 years) reduction, a competent (no regurgitation/⩽IIo regurgitation) MV in 96.6% of cases and positive left ventricular (LV) remodelling.