The role of Willis circle variations during unilateral selective cerebral perfusion: a study of 500 circles

OBJECTIVES

During unilateral selective cerebral perfusion (uSCP), with right axillary artery or brachiocephalic trunk cannulation, the brain receives blood only via the right common carotid artery and right vertebral artery (VA). The left hemisphere is perfused mainly through the circle of Willis (CW). However, at least 50% of individuals have some variation in the CW. The aim of the present work was to study the variations in CW and VA that could have an impact on haemodynamics during uSCP.

METHODS

From May 2005 to March 2012, a total number of 250 circles obtained via routine dissection for medico-legal reasons were examined. The external diameters of all CW segments and both VAs were measured. From January 2008 to March 2012, a total number of 250 patients subjected to computed tomographic angiography of the CW were also examined.

RESULTS

Nine evident configurations of the CW that could cause hypoperfusion during uSCP were observed. They were subdivided in to seven types, according to location and the number of major vessels at risk of hypoperfusion. Type IA: hypo/aplasia of left posterior communicating artery (PComA), found in 35.6% of cases; Type IB: hypo/aplasia of anterior communicating artery (AComA), found in 2% of cases; Type IIA: hypo/aplasia of both left PComA and AComA, found in 4.8% of cases; Type IIB: hypo/aplasia of precommunicating (P1) segment of left posterior cerebral artery or right VA, found in 9.2% of cases; Type IIIA: hypo/aplasia of precommunicating (A1) segment of right anterior cerebral artery, found in 6% of cases; Type IIIB: hypo/aplasia of both right VA and AComA, found in 0.2% of cases; Type IV: hypo/aplasia of both right A1 and right VA or both right A1 and left P1, found in 0.8% of cases. All types were present in 58.6% of all examined CWs.

CONCLUSIONS

Our results show that CW variations are present in a significant number of patients. Our data support the need for extensive preoperative examination and meticulous intraoperative monitoring of cerebral perfusion during uSCP. Finally, our data support the superiority of bilateral SCP over uSCP, because most of the variations reported do not have haemodynamic significance during bilateral SCP.

Gender-Specific Effect of CYP2C8*3 on the Risk of Essential Hypertension in Bulgarian Patients

We conducted a case-control study to determine the contribution of polymorphisms in CYP2C8 (CYP2C8*3) and CYP2J2 (CYP2J2*7) to increased risk of coronary artery disease and essential hypertension in Bulgarians. The current analysis included 192 unrelated hypertensive patients, 261 patients with angiographically documented CAD (153 with myocardial infarction and 108 without myocardial infarction), and 496 population controls. The CYP2C8*3 and CYP2J2*7 polymorphisms were genotyped by TaqMan SNP Genotyping Assay. PLINK version 1.07 was used for the statistical analysis. No overall association was observed for the studied polymorphisms with coronary artery disease and essential hypertension. The frequency of -50T mutant allele of CYP2J2*7 was significantly higher in male with coronary artery disease without history of myocardial infarction (OR 2.16 95% CI 1.04-4.48 p = 0.035) compared to population control group, but this association did not survive after Bonferroni correction (p adj = 0.07). A significant association of CYP2C8*3 allele with increased risk of essential hypertension has found in men (OR 2.12 95% CI 1.18-3.81 p = 0.015) and this relationship remained significant after adjustment for multiple comparisons (p adj = 0.03). This is the first study showing significant gene-sex interaction for CYP2C8*3 with twofold increase in the relative risk of essential hypertension and a similar tendency for CYP2J2*7 associated with coronary artery disease without myocardial infarction in Bulgarian males. The association is not seen in females and in the whole group of patients. This result could be partly explained by the effect of estrogens on the vascular tone of coronary arteries and CYP2C8 gene expression.

Estimation and validation of acenocoumarol dosing algorithms in Bulgarian patients with cardiovascular diseases

Aim & Methods: A total of 169 Bulgarian patients were genotyped for CYP2C9*2,*3, VKORC1-1639G>A and VKORC11173C>T. The effect of genetic and nongenetic factors on acenocoumarol dose variability was tested in a derivation cohort of patients and the obtained algorithm was validated in a test cohort.

RESULTS & DISCUSSION

It was found that VKORC-1639G>A (25.5%), CYP2C9*2 (7.8%), CYP2C9*3 (6.1%), age (13.6%) and diagnosis (6.0%) significantly affected acenocoumarol dose variability in the derivation cohort. These factors with additional factors, such as sex (0.1%, p = 0.76), weight (2.6%, p = 0.14) and amiodarone use (3.0%, p = 0.059) accounted for 46.5% and 23.0% of the dose variability for genetic and clinical models, respectively.

CONCLUSION

Based on the results of this investigation, validated clinical and pharmacogenetic algorithms for the prediction of a stable anticoagulant dose were developed, specifically designed for the Bulgarian population.

Acenocoumarol Pharmacogenetic Dosing Algorithms and Their Application in Two Bulgarian Patients with Low Anticoagulant Requirements

BACKGROUND

The anticoagulant therapy with acenocoumarol is generally associated with a high risk of bleeding and thromboembolic events.

PURPOSE

We applied eight already existing acenocoumarol dosing algorithms to Bulgarian patients with low acenocoumarol dose requirements and investigated which of these algorithms would predict most precisely the dose anticoagulant.

MATERIALS AND METHODS

Two patients with Bulgarian origin were referred to the outpatient clinical laboratory of "St. Ekaterina" University Hospital for Cardiovascular Surgery and Cardiology, Sofia, Bulgaria. After obtaining written informed consent, both patients were genotyped for polymorphisms in genes for Cytochrome P450 2C9 (CYP2C9), Vitamin K epoxide reductase (VKORC1), Apolipoprotein E (APOE), and Cytochrome P450 4F2 (CYP4F2).

RESULTS

All applied acenocoumarol dosing algorithms predicted relatively similar doses of coumarin anticoagulant in both patients. However, van Schie et al.'s algorithm allowed more accurate calculation of the optimal dose in our patients with extremely low acenocoumarol requirements. Genotyping of selected polymorphic variants in CYP2C9 and VKORC1 showed that both patients were compound heterozygotes for CYP2C9 (CYP2C9*2/*3) and homozygotes for both variants in VKORC1 (VKORC1 1173 T/T, and VKORC1-1639 A/A). This combination of genotypes suggested high sensitivity to acenocoumarol leading to the low anticoagulant dose requirements (0.25 and 1 mg/day, respectively) needed to reach the target International Normalized Ratio of 2.5-3.5.

CONCLUSIONS

The genotyping of polymorphic variants in VKORC1 and CYP2C9, together with clinical and demographic parameters, can serve for more precise definition of the individual starting and maintenance doses of coumarin derivatives in each patient.

Antithrombotic regimens in patients after coronary artery bypass grafting and coronary endarterectomy

Background: Coronary artery bypass grafting (CABG) remains the gold standard in the treatment of complex chronic forms of coronary heart disease (CHD). Coronary endarterectomy (CEAE) is a useful adjunctive technique to CABG in patients with diffuse coronary artery disease. In order to maintain the patency of the coronary arteries and graft conduits, various antithrombotic protocols have been introduced over the years, combining various antiplatelet and anticoagulant drugs, but still there is no consensus.

Aim: The aim of the study is to compare results between two antithrombotic regimens after CEAE. The first one is a combination of acenocoumarol combined with acetylsalicylic acid (ASA), the second regimen is a dual antiplatelet therapy (DAPT) of clopidogrel combined with ASA.

Material and methods: We retrospectively reviewed 56 consecutive patients (60 ± 8.2 years) undergoing isolated CABG in association with CEAE between January 2018 and December 2019. In the postoperative period, patients were divided into two groups according to the antithrombotic regimens described above. Twenty-four were in the ASA and acenocoumarol group (AA) and 32 were in the ASA and clopidogrel group (AC). Patients were followed up to 30 days after the operation and we access the mortality rate, new ECG changes, levels of myocardial fraction of creatinine phosphokinase (CPK-MB), left ventricular systolic function, pericardial or pleural effusions requiring drainage or revision for bleeding.

Results: Operative mortality was 3,6 %. No differences in the antithrombotic efficacy of the two regimens. A significantly higher level of hemorrhagic complications was observed in the ASA + acenocoumarol treatment group.

Conclusion: Dual antiplatelet therapy (DAPT) after CABG and coronary endarterectomy is an effective pharmacological regimen in regard to 30-day postoperative outcomes and is considerably safety in terms of bleeding complications.

[Multiple coronary endarteriectomy in patients with diffusial coronary disease]

In recent years the profile of patients with CAD is continuously changing, often with previous operation or stenting. Multiple coronary endarterectomies have been utilized as an adjunct to CABG in this select group of patients to achieve complete revascularization because of the diffuse CAD.

METHODS

Between January 1997 and December 2001 eighty eight consecutive patients undergoing first time CABG with more than two CE were compared with a control group of 967 patients undergoing CABG without CE.

RESULTS

More than 9% of the CABG patients need two or more endarterectomies, with involvement of the RCA in 96% and LAD in 59%. The extended time of aortic clamping and the higher rate of perioperative MI lead to higher mortality in Group 1 without significant difference between groups. The 5 years survival was 69% in Group 1 and 84% in Group 2.

CONCLUSIONS

The operative results--mortality and morbidity, are similar in both groups instead of the highest complexity of the procedures with multiple endarterectomies. The use of this method together with CABG allows complete revascularization in 10% of the operated patients with diffuse atherosclerosis.

[Intraoperative transesophageal echocardiography in patients with surgical valve repair]

For a period of 13 months (from April 1993 till May 1994) 14 patients (5 men and 9 women) have been examined intraoperatively with transesophageal echocardiography. Nine of the patients were with mitral valve lesion, three of them with mitral valve lesion, complicated with tricuspidalisation, one patient with mitral-aortic valve lesion and high grade tricuspid regurgitation and one patient with aortic valve disease. The purpose of the intraoperative transesophageal echocardiography was to surgical valve repair by measuring the residual stenosis and regurgitation. Intraoperative transesophageal echocardiography evaluation was made by biplane two-dimensional echocardiography, colour Doppler mapping and pulse wave Doppler after CPB before sternum closure. In 13 of the examined patients the effect of the surgical valve repair was assessed by transesophageal echocardiography as very good. In one of the cases intraoperative transesophageal echocardiography indicated aortic and mitral valve replacement because of high grade aortic and mitral replacement, persisting after surgical valve repair of both valves. Intraoperative transesophageal echocardiographic findings were compared with postoperative transesophageal echocardiography before dehospitalisation of the patients. The results of both echocardiographic examinations, correlate to a great extent. The existing difference in assessment of the degree of valvular lesions is due to the specific intraoperative haemodynamic situation. Intraoperative transesophageal echocardiography is a valuable method in assessment of surgical valve repair.

[The surgical reconstruction of the chest wall using muscle flaps in patients with mediastinitis following heart operations]

An assessment is made of the results of plastic closure of the chest in cases presenting mediastinitis. The analysis covers nineteen patients with a history of mediastinitis following open-heart surgery, treated by the same method of plastic reconstruction of the chest. The technique of plastic closure of the chest using a rotation muscle flap (pectoralis and right rectus abdominis muscles) is described.

[The renaissance of lumbar sympathectomy]

The question addressed was whether the use of sympathectomy was of benefit in non-revascularisable critical leg ischaemia. Altogether 387 papers were found, of which 13 represented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses were tabulated. We conclude that lumbar sympathectomy is a minimally invasive procedure with a low complication rate. Randomized controlled trials have failed to identify any objective benefits for lumbar sympathectomy, but subjective improvements in symptoms for patients with highly symptomatic critical leg ischaemia have been consistently demonstrated in multiple cohort studies with sustained symptom improvements in approximately 60% of patients. Lumbar sympathectomy is in process of renaissance and should be considered for symptomatic patients with critical leg ischaemia as an alternative to amputation in patients with otherwise viable limbs.

Surgical strategy for patients undergoing carotid endarterectomy

Carotid endarterectomy (CEA) is a surgical intervention that aims to reduce neurological symptoms in carotid atherosclerosis and prevent brain damage and subsequent permanent neurological deficit.

AIM

To study the major risk factors, surgical techniques, applied diagnostic methods and perioperative complications occurred in patients undergoing CEA.

MATERIALS AND METHODS

496 surgical interventions on the occasion of stenosis and/or occlusions of the carotid arteries were performed for the period 1987-2009 at the department of Vascular Surgery and Angiology of "St. Ekaterina"- University Hospital - Sofia. All patients were operated using standard access under general or local anaesthesia. During surgeries, the evaluation of cerebral hemodynamics and function was performed by transcranial Doppler Ultrasound (TCD) and cerebral oximetry (CO). Carotid shunting was selectively applied in cases of deterioration of the values of CO and TCD during cross clamping of the carotid arteries.

RESULTS

With the highest relative share among cerebrovascular complications was stroke with 2.7% share in the group of asymptomatic patients and 1.7%--in the symptomatic group. When considering the other types of complications with the largest relative share were cardiac complications in both groups of patients--hemodynamic disorders and myocardial infarction.

CONCLUSION

Low values of postoperative mortality and stroke after CEA in our study are comparable with other leading centers, proving that CEA is safe and effective surgical procedure for stroke prevention in both symptomatic and asymptomatic patients. Accurate perioperative diagnostic allows a good approach for choosing the correct surgical strategy.

[Analysis of the results of femoro-popliteal arterial bypasses depending on the clinical stage of disease]

The strategy of treating infra inguinal arterial lesions according to the clinical Fontaine stage is very difficult and complicated. Critical limb ischemia is considered a strong indication for revascularization without delay. It is still not clear what operative treatment should be chosen for patients in Fontaine stage II. Early femoro-popliteal bypass reconstruction is a new practical doctrine and the wise alternative before the onset of severe and irreversible changes in the peripheral arterial vessels and the microcirculation. This conception takes a very important part in the evaluation of the long-term perspective of patients.

[Valve repair for mitral regurgitation--early and late results]

Mitral valve repair for regurgitation has many advantages over mitral valve replacement. However, durability and reoperation after repair still remain major problems. We examined the outcome of mitral repair for valve regurgitation and analyzed several pre- and intraoperative factors to determine their impact on mortality and morbidity.

METHODS

From January 1990 to December 2000, 69 patients underwent mitral valve repair. The mean age was 52.8 years, and 82.6% were NYHA class III or IV. The causes of mitral valve disease were ischemic in 32, rheumatic in 20 and degenerative in 17 patients. Mitral valve repair was accomplished by Carpentier's techniques, Key commisuroplasty and ring implantation.

RESULTS

There were 5 early and 6 late deaths in the ischemic group and no early mortality and two late deaths in the mixed rheumatic and degenerative group. Seven patients needed reoperation, 4 in the ischemic group and 3 with rheumatic disease. Actuarial overall survival at 5 years was 100% in rheumatic, 86% in degenerative and 75% in ischemic patients.

CONCLUSIONS

Mitral valve repair for mitral regurgitation provides excellent results and long-term survival in rheumatic and degenerative disease. The ischemic etiology is the most important predictor for early death and poor long term survival.

[Endovascular recanalisation of subclavian artery stenotic-occlusive lesions]

Recently, percutaneous transluminal angioplasty (PTA) with stent placement has gained greater acceptance for the treatment of hemodynamically significant atherosclerotic lesions involving the brachiocephalic, subclavian and vertebral vessels. PTA is performed instead of extratoracic bypass surgery, which is associated with several risks and complications. Main indications for PTA and stent include short occlusions and elderly patients with increased surgical risk. We present 4 cases with occlusion of the left subclavian artery, including 1 case ofthombosed distal anastomosis of carotid-subclavian bypass.

[Combined surgical treatment of patients with huge aortic abdominal aneurysms associated with coronary artery lesions]

The objective of this study was to define the perioperative risk of simultaneous operations in patients with abdominal aortic aneurysm (AAA) associated with coronary artery disease (CAD). The hospital data of 30 patients with coexistent severe symptomatic AAA and significant CAD, who underwent one stage surgery of the abdominal aorta and the coronary arteries was retrospectively analysed. Most of the pts.--28 were male and only 2 female. The average age consisted 57.7 years. Infrarenal AAA (diameter over 5 cm) was presented in 25 patients and suprarenal extension was in presented in 5 pts, while all patients with coexisting CAD had three vessels disease and significant impairment of left ventricular function (23 pts with ejection fraction (EF) < 50% and 10 pts < 30% EF). The resections of AAA in pts. undergoing simultaneous coronary artery procedure were performed on cardiopulmonary bypass (CPB) and moderate hypothermia. There were 2 early postoperative deaths (6.66%) and 5 major nonfatal postoperative complications (16.6%). Our experience with simultaneous surgery of coexistent huge AAA and CAD demonstrated that: a) Combined procedure can be performed safely in patients with significant AAA and CAD. b) The overall early operative mortality and morbidity after combined surgery compare favourably with the results after CABG of patients with impaired left ventricular function. c) Simultaneous operation seems to be more favourable in patients with coexistent AAA and CAD regarding the high risk of aneurysmal rupture, saving them also the potential morbidity and eventually fatal complications associated with the second procedure. d) Even the management of suprarenal and huge infrarenal AAA can be carried out easier and with less risk of complications under the protection of CPB.

[Surgical treatment of acquired mitral valve diseases--five-year analysis of early and late results]

The indications for mitral valve repair or mitral valve replacement are worldwide accepted, but they still depend of the personal experience of the surgeon and the tradition in the respective cardio-vascular clinic. Valve repair had many advantages over the replacement, but the long-term durability and the reoperations remain a major problem. In this retrospective review we examine the five years results of the surgical treatment of mitral valve diseases and the factors influencing the choice of the operation, the mortality and morbidity.

METHODS

From January 1998 to December 2002, 76 patients underwent mitral valve repair and 194 underwent mitral valve replacement. The mean age was 50.6 years, and 52.8% were NYHA class III or IV. The causes of mitral valve disease were ischemic in 45, rheumatic in 133, degenerative in 68 and endocarditis in 18 patients. Mitral valve repair was accomplished by Carpentier's techniques, Key, Alfeiri or ring implantation and mitral valve replacement with mechanical or biologic valve.

RESULTS

In the ischemic group early mortality occurred in 7 patients (15.5%), in endocarditis group in 3-16.6%, in degenerative group in 2 (2.9%) and in the rheumatic group in 3 (2.2%). Overall mortality in the replacement group was 5.1% and in the repair group (6.5%). Six patients needed reoperation in the repair (7.8%) and 12 patients in the replacement group (6.1%). Survival at 5 years was 90% in the repair and 83% in replacement patients.

CONCLUSIONS

Mitral valve repair are used almost always in ischemic and degenerative etiology, but they also show good results and long-term survival in cases of rheumatic mitral valve disease. The ischemic etiology, endocarditis and bad function of the left ventricle are the most important predictors for early death and poor long-term survival.

ENDOVASCULAR TREATMENT OF AN ANEURYSM OF THE SPLENIC ARTERY

Aneurysms of the splenic artery account for about 60% of all aneurysms of visceral arteries. Most of them are asymptomatic until rupture and are discovered accidentally, usually after an imaging study. The treatment is surgical or endovascular depending on the type, location and size. We present a case of a patient with an asymptomatic, accidentally found aneurysm of the splenic artery which we successfully treated with a covered stent. The control CT-angiography on 6th month showed patent stent and totally occluded aneurysm. It is very important in cases of acute abdomen and hemorrhagic shock to think of a ruptured aneurysm. In these cases the treatment of choice is endovascular as it is mini-invasive and organ-saving.

[Adjuvant and individual application of lumbar sympathectomy at patient with arterial disease in lower limb]

The first lumbar sympathectomy for treatment of arterial occlusive disease of the lower extremity was performed in 1924 by Julio Diez of Buenos Aires. The standart anatomy textbooks indicate, as a rule that the lumbar sympathetic trunk contains four or five ganglia. The overall anatomic denervation is important for achievement of an adequate sympathectomy of a given segment of an extremity. Criteria and indications for complete sympathetic block are still not clear. Exceptionally important for the improvement of the reology of the lower limbs is the option for a direct increase of the collaterals' debit which could be achieved by extensive profundoplasty. As an addition to the arterial reconstructions, the sympathectomy increases the passability of small vessel anastomosis and the recovery of traumatized arteries. Unilateral or bilateral lumbar sympathectomy is performed by retroperitonal access. From 01.01.2008 till 01.11.2008 in our clinic were performed 117 isolated and after arterial reconstruction lumbar sympathectomies.

[Endovascular or surgical treatment of the carotid arteries]

Ischemic stroke is the third most common cause of death right after myocardial infarction and malignancies. Most cases of stroke are due to extracranial carotid atherosclerotic disease. The percutaneous transluminal angioplasty and stenting of the carotid arteries have emerged as an alternative to the standart carotid endarterectomy mainly because they are less invasive procedures. Carotid stenting with or without the use of neuroprotection devices proves to be effective in high-risk patients with carotid stenosis. Nevertheless, there is no clear proof that endovascular techniques outmatch the classic surgical methods.

SURGICAL STRATEGY FOR PATIENTS UNDERGOING CAROTID ENDARTERECTOMY

Carotid endarterectomy (CEA) is a surgical intervention that aims to reduce neurological symptoms in carotid atherosclerosis and prevent brain damage and subsequent neurological deficit.

AIM

To study the major risk factors, surgical techniques, applied diagnostic methods and perioperative complications occurring in patients undergoing CEA.

MATERIALS AND METHODS

496 surgical interventions on the occasion of stenoses and/or occlusions of the carotid arteries were performed for the period 1987-2009 at the department of Vascular Surgery and Angiology of "St. Ekaterina" - University Hospital - Sofia. All patients were operated using standard access under general or local anaesthesia. During surgeries, evaluation of cerebral hemodynamics and function was performed by transcranial Doppler Ultrasound (TCD) and cerebral oximetry (CO). Carotid shunting was selectively applied in cases of deterioration of the values of CO and TCD during cross clamping of the carotid arteries.

RESULTS

The highest relative share among cerebrovascular complications took stroke with 2.7% share in the group of asymptomatic patients and 1.7% - in the symptomatic group. Considering the other types of complications with the largest relative share were cardiac complications in both groups of patients - hemodynamic disorders and myocardial infarction.

CONCLUSION

Low values of postoperative mortality and stroke after CEA in our study are comparable with other leading centers, proving that CEA is safe and effective surgical procedure for stroke prevention in both symptomatic and asymptomatic patients. Accurate perioperative diagnostic allows a good approach for choosing the correct surgical strategy.