SCIENTIFIC COUNCIL DSc.06/2025.27.12.Tib.08.01 AT THE REPUBLICAN SPECIALIZED SCIENTIFIC AND PRACTICAL MEDICAL CENTER OF SURGERY NAMED AFTER ACADEMICIAN V. VAKHIDOV ON AWARD OF SCIENTIFIC DEGREES

REPUBLICAN SPECIALIZED SCIENTIFIC AND PRACTICAL MEDICAL CENTER OF SURGERY NAMED AFTER ACADEMICIAN V. VAKHIDOV

ISMATOV ABDULLA ATAULLAYEVICH

ISCHEMIC HEART DISEASE COMBINED WITH MODERATE MITRAL VALVE INSUFFICIENCY: OPTIMIZATION OF SURGICAL TREATMENT TACTICS

14.00.34 - Cardiovascular Surgery

ABSTRACT OF THE DISSERTATION OF DOCTOR OF PHILOSOPHY (PhD) IN MEDICAL SCIENCES

TASHKENT - 2026

The subject of the Doctor of Philosophy (PhD) dissertation is registered in the Higher Attestation Commission under the Ministry of Higher Education, Science and Innovation of the Republic of Uzbekistan under No. B2023.1.PhD/Tib3422.

The dissertation was performed at the Republican Specialized Scientific and Practical Medical Center of Surgery named after Academician V. Vakhidov.

The abstract of the dissertation is available in three languages (Uzbek, Russian, English (summary)) on the website of the Scientific Council (www.rscs.uz) and on the Information and Educational Portal "ZiyoNet" (www.ziyonet.uz).

The defense of the dissertation will take place on «___» ____________ 2026 at ____ at the meeting of the Scientific Council DSc.06/2025.27.12.Tib.08.01 on award of scientific degrees at the Republican Specialized Scientific and Practical Medical Center of Surgery named after Academician V. Vakhidov (Address: 100115, Tashkent city, Kichik Khalka Yoli str., 10. Phone: (+99871) 277-69-10; fax: (+99871) 277-26-42; e-mail: cs.75@mail.ru).

The dissertation can be reviewed at the Information Resource Center of the Republican Specialized Scientific and Practical Medical Center of Surgery named after Academician V. Vakhidov (registered under No. 216). Address: 100115, Tashkent city, Kichik Khalka Yoli str., 10. Phone: (+99871) 277-69-10; fax: (+99871) 277-26-42.

The abstract of the dissertation was distributed on «___» ____________ 2026.

F.G. Nazyrov
Chairman of the Scientific Council on award of scientific degrees, Doctor of Medical Sciences, Professor, Academician

S.A. Babadjanov
Scientific Secretary of the Scientific Council on award of scientific degrees, Doctor of Medical Sciences

O.D. Eshonkhodjayev
Chairman of the Scientific Seminar at the Scientific Council on award of scientific degrees, Doctor of Medical Sciences, Professor

INTRODUCTION (annotation of PhD dissertation)

Relevance and necessity of the dissertation topic. Coronary artery disease (CAD) remains one of the main problems of modern cardiology. It is characterized not only by high incidence rates, but also by the severity of its complications. Chronic myocardial ischemia often serves as a trigger for the development of ischemic cardiomyopathy, accompanied by global pathological remodeling of the left ventricle. A special place in the structure of this pathology is occupied by moderate mitral regurgitation, which reflects a complex clinical stage of disease progression. Despite its "moderate" status, due to the complexity of the developmental mechanisms, its contribution to the destabilization of the patient's condition is very significant. According to scientific data, "...a moderate degree of valvular dysfunction significantly worsens the prognosis, reduces exercise tolerance, worsens the quality of life of patients, and statistically significantly increases the risk of severe cardiovascular complications leading to a fatal outcome"[1]. Despite significant successes achieved in the surgical treatment of this pathology, the choice of an optimal treatment strategy to date remains an urgent and complex clinical task.

In global clinical practice, discussions continue regarding the advisability and volume of surgical correction of moderate mitral regurgitation in patients with ischemic cardiomyopathy. In particular, there is no consensus on the need to perform mitral valve repair simultaneously with coronary artery bypass grafting (CABG). The question remains debatable whether restoring coronary blood flow alone without additional valve correction leads to a reduction in the degree of mitral regurgitation, and whether combined intervention provides long-term results such as reverse left ventricular remodeling, improvement in NYHA functional class, and better quality of life. At the same time, the potential increase in the risk of postoperative complications, duration of cardiopulmonary bypass, and mortality rate when performing a combined intervention, especially in polymorbid patients, is discussed, which is why research results on this issue remain contradictory to date. Based on the above, further in-depth study of this issue retains its relevance.

In our country, consistent measures are being implemented to develop the healthcare system, bring the medical industry into line with international standards, including early diagnosis, treatment, and prevention of various somatic diseases. The seven priority directions of the Development Strategy of New Uzbekistan for 2022–2026 define the tasks "to improve the quality of qualified medical care provided to the population"[2]. The implementation of these tasks, in particular improving the treatment outcomes for patients with coronary artery disease, conditions the advisability of conducting research aimed at improving the effectiveness of surgical treatment methods for this pathology, given its high medical and social importance.

This dissertation research to a certain extent serves to implement the tasks outlined in the Decrees of the President of the Republic of Uzbekistan: No. UP-60 dated January 28, 2022 "On the Development Strategy of New Uzbekistan for 2022–2026", No. UP-6110 dated November 12, 2020 "On measures to introduce fundamentally new mechanisms into the activities of primary healthcare institutions and further improve the healthcare system", as well as in Resolutions: No. PP-4891 dated November 12, 2020 "On additional measures to ensure public health through further increasing the effectiveness of medical prevention work", No. PP-5124 dated May 25, 2021 "On additional measures for the comprehensive development of the healthcare system", No. PP-5199 dated July 28, 2021 "On measures for further improvement of the specialized medical care system in the field of healthcare", and other regulatory legal acts related to this activity.

Compliance of the research with the priority directions of science and technology development of the Republic. This study was carried out in accordance with the VI priority direction of science and technology development of the Republic — «Medicine and Pharmacology».

Degree of study of the problem. It has been established that myocardial ischemia arising against the background of coronary artery disease leads to remodeling of the left ventricle and mitral valve ring, which, in turn, causes a change in the geometry of the valvular apparatus. Ischemic mitral insufficiency is initially considered a disease not of the mitral valve, but of the left ventricle (Grayburn P.A., Sannino A., 2019). It has been proven that the main mechanism of ischemic mitral regurgitation development is myocardial ischemia causing left ventricular remodeling, displacement of papillary muscles and their relative shortening, resulting in excessive tension of the mitral valve leaflets and reduced closure force (Asgar A.W., Mack M.J., 2015). Progression of papillary muscle dysfunction, left ventricular dyssynchrony, and mitral valve ring dilation also play an important role in the development of mitral insufficiency. Systolic tension of the mitral valve leaflets (restriction of their mobility) is considered one of the main pathogenetic mechanisms of mitral insufficiency (Chehab O., Roberts-Thomson R., Ng Yin Ling., 2020).

The results of conservative treatment of this pathology remain unsatisfactory: five-year mortality in ischemic mitral regurgitation reaches 60–100% depending on the severity of mitral regurgitation, the extent of coronary artery disease, and preserved left ventricular function (Haberman D. et al., 2022). In this regard, ischemic mitral regurgitation continues to be a complex problem in cardiac surgery. Despite significant progress in this field, many issues related to the choice of optimal surgical tactics remain unresolved. Furthermore, there is a lack of prospective studies dedicated to myocardial revascularization strategies in this category of patients.

In general, summarizing global experience, it should be noted that patients with ischemic mitral insufficiency belong to a group with an unfavorable prognosis; choosing a treatment method for this pathology poses a serious challenge for cardiologists and cardiac surgeons; high mortality rates during medical therapy and the advancement of coronary surgery contribute to expanding indications for CABG in these patients. In addition, the feasibility of performing off-pump CABG in patients with ischemic mitral insufficiency remains undecided and requires further research.

In Uzbekistan, the study and optimization of surgical treatment methods for patients with CAD complicated by ischemic mitral insufficiency remain an urgent task of modern cardiology and cardiac surgery. To date, a limited number of scientific studies on this problem have been conducted in our country. In particular, in scientific publications by Aliyev Sh.M., Khalikulov Kh.G. et al., main attention was paid to patients with relatively preserved anatomical and functional parameters of the heart.

Considering that remodeling as a complication of CAD is a progressive process, issues of comprehensive evaluation of indications and effectiveness of surgical treatment in patients with severely reduced anatomical and functional parameters of the left ventricle and verified ischemic cardiomyopathy remain insufficiently studied. Therefore, this direction requires additional research and represents significant scientific and practical interest.

Connection of the dissertation research with institutional research plans. The dissertation research was carried out within the framework of scientific project AL-492105342 (2022–2025) "Optimization of diagnosis, tactics, and treatment outcomes in patients with coronary artery disease using modern technologies", in accordance with the scientific plan of the Republican Specialized Scientific and Practical Medical Center of Surgery named after Academician V. Vakhidov.

Objective of the study: to improve the outcomes of surgical treatment of coronary artery disease complicated by moderate ischemic mitral valve insufficiency based on a comparative analysis of surgical treatment methods.

Research tasks are as follows:
- study of immediate and long-term results of isolated coronary artery bypass grafting (CABG) and CABG performed in combination with mitral valve (MV) intervention;
- determination of risk factors influencing mortality, immediate, and long-term results after isolated CABG and combined CABG + MV intervention;
- assessment of quality of life indicators in patients in the long-term period after isolated CABG and combined CABG + MV intervention, as well as determining the dependence of the results on the scope of surgical intervention;
- development of an algorithm for choosing surgical tactics in patients with coronary artery disease (CAD) and ischemic mitral regurgitation (IMR).

Object of the study. 80 CAD patients complicated by IMR operated on during 2018–2023 at the Jizzakh branch of the Republican Specialized Scientific and Practical Medical Center of Cardiology and "American Hospital" JV LLC, Tashkent city.

Subject of the study is a comparative analysis of surgical treatment outcomes for CAD complicated by moderate IMR, identification of risk factor groups affecting survival, and evaluation of patient quality of life and clinical outcomes in immediate and long-term postoperative periods.

Research methods. To achieve the set objective and solve the tasks, general clinical, laboratory, instrumental, special, and statistical research methods were used.

Scientific novelty of the dissertation research is as follows:
- proved that in patients with ischemic cardiomyopathy complicated by moderate mitral insufficiency, performing CABG in combination with mitral valve repair significantly reduces the recurrence rate of significant mitral regurgitation in the long-term period compared to isolated CABG due to stabilization of the mitral annulus;
- proved a reliable correlation of risk factors such as age >70 years, diabetes mellitus, chronic kidney disease, and left ventricular ejection fraction <30% with the development of early postoperative complications and adverse outcomes;
- confirmed that CABG performed in combination with mitral valve repair has a more pronounced positive effect on heart remodeling parameters, including dynamic increase in LVEF and reduction of end-diastolic and end-systolic dimensions, compared to isolated myocardial revascularization;
- proved that an individualized surgical treatment tactic taking into account the patient's polymorbid status provides an optimal balance of efficacy and safety in CAD patients with secondary mitral insufficiency.

Practical results of the study are as follows:
- established that combined surgical treatment (CABG + mitral valve repair) is important for improving long-term prognosis in CAD with moderate IMR, proving its feasibility and effectiveness;
- demonstrated the necessity of an individual approach in defining indications for choosing specific surgical options in CAD patients with IMR, evaluating its feasibility and limitations;
- confirmed the high efficiency of modern echocardiographic methods in diagnosing pathognomonic signs of LV remodeling and evaluating outcomes of different surgical interventions (isolated CABG vs. combined CABG + MV repair);
- developed key criteria for standardizing methodological approaches to optimize surgical tactics in patients with CAD and moderate ischemic mitral insufficiency.

Reliability of research findings. The reliability of the research results is justified by the use of modern laboratory and instrumental research methods widely applied in clinical practice, as well as the fact that all findings and conclusions are based on evidence-based medicine principles, an adequate volume of clinical material, and rigorous statistical analysis.

Scientific and practical significance of the study. The scientific significance lies in expanding knowledge regarding the application of surgical algorithms in CAD and IMR management and forming theoretical foundations for choosing optimal surgical strategies.

The practical significance consists in optimizing tactical and technical aspects of surgical treatment for CAD and IMR patients, standardizing methodological approaches, and enhancing the role of national cardiac surgery in CAD treatment on a global level.

Implementation of research results. Approved by the decision of the Scientific and Technical Council under the Ministry of Health of the Republic of Uzbekistan (protocol No. 31/01 dated December 17, 2025) based on the research results:

First scientific novelty: implemented into clinical practice of the Karshi branch of the Republican Specialized Center of Cardiology (order No. 74/1t dated Sept 29, 2025) and Bukhara State Medical Institute clinic (order No. 10 dated Nov 24, 2025). Social efficiency: new intracardiac hemodynamics assessment approaches improved diagnostic accuracy, reduced errors, ensured timely treatment, and reduced disability rates. Economic efficiency: reduced intensive care stay from 1.3±0.3 to 1.2±0.3 days, saving 200,000 UZS per patient (total 8,000,000 UZS for 40 patients);

Second scientific novelty: implemented into clinical practice of Karshi branch of RSMC Cardiology and Bukhara State Medical Institute clinic. Social efficiency: early risk predictor identification helped optimize patient management and reduce perioperative complications. Economic efficiency: unified diagnostic algorithm reduced redundant examinations, saving 950,000 UZS per patient (total 38,000,000 UZS annually for 40 patients);

Third scientific novelty: implemented into clinical practice of Karshi branch of RSMC Cardiology and Bukhara State Medical Institute clinic. Social efficiency: improved patient quality of life, physical activity, and reduced re-admission risks. Economic efficiency: reduced postoperative complication treatment costs by 1,500,000 UZS per patient (total 12,000,000 UZS annually);

Fourth scientific novelty: implemented into clinical practice of Karshi branch of RSMC Cardiology and Bukhara State Medical Institute clinic. Social efficiency: social adaptation improved, quality of life increased, and socio-economic burden reduced. Economic efficiency: multidisciplinary protocols ensured rational resource utilization and reduced direct/indirect healthcare costs.

Approbation of research results. Results were discussed at 3 scientific-practical conferences (1 international, 2 national).

Publications. A total of 10 scientific papers were published on the topic, including 4 articles in journals recommended by the Higher Attestation Commission (3 national, 1 foreign), 1 methodological recommendation, and 1 software copyright certificate.

Volume and structure of the dissertation. The dissertation consists of an introduction, four chapters, conclusions, practical recommendations, and a reference list, totaling 119 pages.

MAIN CONTENT OF THE DISSERTATION

In the introduction, the relevance, objective, tasks, object, subject, scientific novelty, practical significance, and structure of the research are outlined.

In the first chapter «CAD combined with moderate mitral valve insufficiency: optimization of surgical tactics (literature review)», epidemiological, pathogenetic, diagnostic criteria, and current clinical trends are reviewed.

In the second chapter «General characteristics of clinical material and methods», 80 patients operated on between 2018–2023 were analyzed (Control Group: isolated CABG, n=40; Main Group: CABG + MV repair, n=40).

Fig. 1. Representation of concomitant pathologies in the study groups.

In the third chapter «Immediate results of surgical treatment of patients with CAD and IMR», outcomes were analyzed including hemodynamic recovery, bypass grafting extent, and early postoperative complications.

Fig. 2. Distribution of patients in the study groups by the number of coronary bypass grafts performed.

Fig. 3. Intraoperative characteristics in the study groups.

Table 1. Mechanical ventilation duration, ICU, and hospital stay metrics.

Table 2. Early postoperative EchoCG parameters

Table 3. Univariate analysis of risk factors identified the following significant predictors of mortality and adverse outcomes.

In the fourth chapter «Long-term results of surgical treatment of coronary artery disease and ischemic mitral regurgitation», outcomes were followed up for up to 3 years in 38 control patients and 39 main group patients.

Table 4. Distribution of patients by surgical outcomes in the long-term observation period

Fig. 4. Dynamics of patient distribution according to the New York Heart Association (NYHA) classification in the long-term period

Table 5. Comparative EchoCG parameters 6 months after surgery

Table 6. Comparative EchoCG parameters 1 year after surgery

Table 7. Comparison of MR dynamics between groups

Fig. 7. Quality of life comparison by SF-36 one year after surgery

CONCLUSIONS

1. Comparative analysis of immediate surgical results showed that CABG + MV repair did not lead to an improvement in early or overall mortality rates or early postoperative parameters compared to isolated CABG alone. However, MV intervention resulted in a reduced frequency of recurrent significant MR (from 12.5% to 5%; p<0.001) and potential improvement in NYHA functional class in 85.2% of cases (p<0.001).

2. Univariate risk factor analysis identified the following significant predictors of adverse surgical results in CAD and IMR: age >70 years (χ2=11.45, 95% CI=2.0–6.0, p=0.0009), LVEF <30% (χ2=12.67, 95% CI=2.1–6.3, p=0.0004), presence of DM (χ2=7.29, 95% CI=1.3–4.7, p=0.006), and CKD (χ2=9.18, 95% CI=1.9–5.8, p=0.002).

3. Quality of life analysis following CAD and IMR surgery showed that combined MV and CABG intervention yields significantly superior physical, emotional, and social well-being in patients in the long-term period compared to isolated myocardial revascularization.

4. The developed decision-making algorithm for choosing surgical tactics in CAD and IMR patients, incorporating evaluation of MR degree, LV function, valve anatomy, and comorbidity status, provides an individualized approach. This allows reducing complications, reoperations, and mortality risk through combined CABG + MV repair, while improving treatment efficacy and long-term quality of life.

[1] Nishimura et al., 2020 (ACC/AHA Guidelines) Nishimura R.A., Otto C.M., Bonow R.O. et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease. Circulation, 2021.
[2] Decree of the President of the Republic of Uzbekistan No. UP-60 dated January 28, 2022 "On the Development Strategy of New Uzbekistan for 2022–2026".