Comparing Clinical and Hemodynamic Parameters between the Two Aortic Valve Replacement in Patients with Severe Aortic Stenosis.

Context: Various techniques have been proposed for suturing following prosthetic aortic valve implantation, but each has its potential side effects such as patient-prosthesis mismatch (PPM) and paravalvular leak (PVL). Aims: In the present study, we aimed to compare the postoperative sequels of aortic valve replacement (AVR) following the use of two suturing techniques including from the inside of the aorta as the common and classic suturing techniques as compared to new approach including from the outside of the aorta. Settings and Design: This cross-sectional study was performed on patients suffering from symptomatic severe aortic valve disease and candidates for AVR in one of three referral hospitals for cardiovascular disease patients in Shiraz from 2019-2021. Subjects and
Methods: The patients underwent one of the two considered surgical techniques for AVR including traditional approach (n = 60) or the tested approach (suturing from the outside of the aorta) (n = 30). Statistical Analysis Used: For statistical analysis, results were presented as mean ± standard deviation for quantitative variables and were summarized by frequency (percentage) for categorical variables.
Results: PVL and PPM were revealed in none of the participants undergoing the tested approach, while the pointed complications were found in 41.7% and 25.0% of patients underwent traditional approach, respectively, indicating a significant difference. There was no evidence of abnormal dimensionless valve index (DVI) in the patients undergoing sutures from outside the aorta, whereas the rate of DVI abnormality in the patients undergoing traditional procedures was shown to be 18.3%. The mean aortic valve gradient was significantly higher in the group scheduling for the traditional surgical method. Conclusions: Applying new suturing method as suturing from the outside of the aorta, due to the selection of appropriate valve size, the risk for adverse consequences including PPM, PVL, or DVI can be significantly reduced. Copyright:

INTRODUCTION

The prevalence of aortic valve disease has increased in the community with age, with about 3%–4% reported in adults.[1] The various causes of aortic valve diseases include congenital problems, rheumatic diseases, connective tissue diseases, and calcified degeneration.[23] Aortic valve replacement (AVR) is one of the most common heart surgeries worldwide. Despite advances in prosthetic valve designs, improving the quality of surgical techniques, and improving postoperative care, postoperative complications of the AVR remain a major cause of mortality and morbidity.[4] Although transcatheter aortic valve replacement (TAVR) is tolerated well in affected patients with proper sequels, surgical aortic valve replacement remains an acceptable surgical procedure for aortic problems.[5] AVR is an effective procedure for treating symptomatic and severe aortic stenosis since 1960. Over time, with the improvement of the surgical procedure, the risks for such procedure have decreased and survival and quality of life of patients have accordingly improved.[6] Various techniques employed to replace aortic valve include the use of bioprosthetic valve sourced from using animal valve or pericardium, the use of mechanical valve made by tolerable synthetic materials for the body such as metal and carbon, pulmonary autograft (removing the aortic valve and replacing with patient's own pulmonary valve) and prosthetic valve replacement by TAVR.[78]

Despite many advances in surgical techniques along with qualification of prosthetic valves, complications of valve replacement procedures such as infective endocarditis, dehiscence, paravalvular leak (PVL), abscess formation, aortic dissection, coronary artery occlusion, mediastinitis, brain stroke, heartbeat irregularity, and arrhythmias remains significant.[910] To reduce the mentioned surgical complications, several methods have been performed by heart surgeons. In the present study, the complications of AVR surgery have been compared between the two surgical techniques for AVR. In the first technique as the traditional approach (suturing from inside the aorta),[11] after a pericardial incision sternotomy, the aorta is clamped at the highest point of the ascending aorta and connected to the pump. By injecting cardioplegic material into the root aorta (systemic cooling) and by pouring cold saline or ice (topical cooling), asystole is induced. In this method, to facilitate the placement of the valve, the surgeon is required to leave a shelf of the valve in the annulus to suture the artificial valve, which in turn causes the selection of a smaller valve size. The prosthetic valve is then sutured from the inside of the aorta to the base (the sutures are sutured from the inside). Shelf retention limits the removal of calcifications and causes the selection of small or inappropriate valve size and occurring patient-prosthesis mismatch (PPM) with the increased likelihood of PVL. In suturing from the outside of the aorta,[12] after the circumference of the aorta has been discarded from the surrounding vessels and tissues, the aorta opens and the patient valve, shelf, and total calcifications are completely removed. The prosthetic valve can be inserted in a suitable size or even larger than the size reported in echocardiography. By choosing a larger size for the valve and using the suture method from the outside, it is expected that the PVL will be completely removed and the gradient on both sides of the valve will be minimized and there will be no PPM problem.

SUBJECTS AND METHODS

This cross-sectional study was performed on patients suffering symptomatic severe aortic valve disease and candidates for AVR in one of three referral hospitals for cardiovascular disease patients in Shiraz from 2019–2021. This study was approved by the Ethics Committee of the Shiraz University of Medical Sciences (IR.SUMS.MED.REC.1399.612) and all the study participants were informed about the study protocol and written consent was obtained before baseline examinations. Based on the surgeon's choice and judgment, the patients underwent one of the two considered surgical techniques for AVR including traditional approach (suturing from inside the aorta) (n = 60) or the tested approach (suturing from the outside of the aorta) (n = 30). Inclusion criteria were the age range of over 18 years with severe aortic stenosis. In this regard, dissatisfaction with continued participation in the study, requiring double AVR, the presence of aortic insufficiency, or needing dissection repair was considered the exclusion criteria. After collecting the baseline characteristics including demographics, medical history and details of surgical procedures, patients were called for echocardiography 2–6 months after surgery. In echocardiography assessment, aortic valve gradient, aortic valve area, dimensionless valve index (DVI), and any evidence of PPM or PVL were assessed. Considering that the process of conducting this research was in line with the usual therapeutic interventions of patients who needed surgery based on the decision of a cardiologist, no intervention was performed beyond what is in accordance with the treatment instructions. To use the patients' clinical information in this study, informed consent was obtained from all patients included in the study or their family and written consent form was completed. It should be noted that to maintain the confidentiality of the identity of the persons under study, no identity information was collected from the individuals in the form of information collection form or otherwise.

For statistical analysis, results were presented as mean ± standard deviation for quantitative variables and were summarized by frequency (percentage) for categorical variables. Continuous variables were compared using t-test or Mann–Whitney test whenever the data did not appear to have normal distribution or when the assumption of equal variances was violated across the study groups. The categorical variables were analyzed using the Chi-square test. P ≤ 0.05 was considered statistically significant. For the statistical analysis, the statistical software SPSS version 23.0 for windows (IBM, Armonk, New York, USA) was used.

RESULTS

The two groups undergoing suturing from inside the aorta as the classic procedure and from outside the aorta as the tested approach were similar in average age (54.65 ± 13.27 years vs. 59.96 ± 11.64 years, P = 0.088) and male gender (56.7% vs. 66.7%, P = 0.361). Characteristics of patients are given in Table 1. The consequences of the procedures in the two studied groups are summarized in Table 2. The patients were matched to the control group with respect to age and gender. First, PVL and PPM were revealed in none of the participants undergoing the tested approach, while the pointed complications were found in 41.7% and 25.0% of patients underwent traditional approach, respectively, indicating a significant difference (P < 0.001). Furthermore, there was no evidence of DVI in the patients undergoing sutures from outside the aorta, whereas the rate of abnormal DVI in the patients undergoing traditional procedures was shown to be 18.3%. The mean aortic valve gradient was significantly higher in the group scheduling for traditional surgical method (P = 0.009). There was no difference in the mean pump time between the two groups. Two patients in the traditional surgical approach but none of the patients in another group required pacemaker. None of the studied participants suffered cerebrovascular accident.

Table 1

Characteristics of patients in the two groups

Item	Suturing from inside the aorta	Suturing from outside the aorta	P
Age	54.65±13.27	59.96±11.64	0.08
Male (%)	56.7	66.7	0.36
Smoking (%)	62.8	64.4	42
Diabetes mellitus (%)	39.1	37.6	33

Table 2

Comparing surgical outcome in the two surgical approaches

Item	Suturing from inside the aorta (n=60)	Suturing from outside the aorta (n=30)	P
PVL, n (%)	25 (41.7)	0	<0.001
PPM, n (%)	15 (25.0)	0	<0.001
DVI, n (%)	11 (18.3)	0	0.014
Aortic valve gradient	14.94±9.17	11.60±4.18	0.009
Orifice valve area (cm2)	0.59±0.11	0.61±0.12	0.13
Abnormal gradient, n (%)	16 (26.7)	0	0.001
Men pump time (min)	53±5	56±4	0.224
Pacemaker insertion, n (%)	2 (3.3)	0 (0.0)	0.256

PVL: Paravalvular leak, PPM: Patient-prosthesis mismatch, DVI: Dimensionless valve index

DISCUSSION

Various techniques have been proposed for suturing following prosthetic aortic valve implantation, but each has its potential side effects such as PVL and PPM. In the present study, we aimed to compare the postoperative sequels of AVR following the use of two suturing techniques including from the inside of the aorta as the common and classic suturing techniques as compared to new approach including from the outside of the aorta. In fact, we firstly hypothesized that suturing by the latter technique may reduce postoperative events such as DVI, PPM, and PVL as well as improve aortic valve gradient following the replacing surgery. According to our results, employing approaching the valve suture from the outside of the aorta by maintaining other stages of reconstructive operation can significantly prevent potential complications of the surgery as considerably reducing PVL, PPM, abnormal DVI, and also aortic valve gradient. Interestingly, it seems that applying the new pointed approach can also reduce the risk for postoperative arrhythmias needing pacemaker implantation. Both complications of PPM and PVL are common in patients undergoing AVR. According to the literature, 70% of AVRs may be accompanied with PPM with severe state in about 20% of them.[13] This event is mainly referred to the lower effective orifice area of the prosthetic valve after valve insertion leading to some degree of obstruction to blood flow across the prosthetic valve.[14] In fact, PPM should be suspected in patients with persistent cardiac symptoms after AVR when there is high prosthetic valve velocity or gradient and a small calculated effective orifice area (<0.65 cm2/m2). Besides, PVL is a potentially serious condition resulting from degeneration of annular tissue, affecting 6%–15% of surgically implanted prosthetic valves and annuloplasty rings.[15] One of the main reasons for appearing such adverse consequences is shown to be insertion of small valvular prosthesis.[16] Thus, it seems that inserting larger prostheses along with aortic root enlargement can be considered to avoid PPM or PVL.[17] In our experience, we could show that using older suturing approach, shelf retention may not allow us the removal of calcifications and causes the selection of small or inappropriate valve size, but in newer approach, the shelf and total calcifications can be completely existed and thus the prosthetic valve can be inserted in a suitable size or even larger than the size expected by initial imaging and thus the pointed adverse events can be successfully prevented.

CONCLUSIONS

As the final conclusion, applying new suturing method as suturing from the outside of the aorta, due to the selection of appropriate valve size, the risk for adverse consequences including PPM, PVL, or abnormal DVI can be significantly reduced and thus the overall outcome of AVR can be acceptable.

Ethical clearance

IR.SUMS.MED.REC.1399.612.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.