Aortic stenosis is one of the most common valvular pathologies in India and worldwide, with a prevalence of 46 for every 100,000 people in northern India. [1] The most common etiology is usually rheumatic, although congenital and degenerative (calcific) causes also contribute significantly to the pathology. Severe AS was defined by at least 1 of the following hemodynamic measurements: transaortic valve peak pressure gradient ≥64 mm Hg, transaortic valve mean pressure gradient ≥40 mm Hg, or aortic valve area ≤1.0 cm2. [2] If patients had AS with a severity that was equal to or higher than the AR severity, they were classified as having AS.Aortic Stenosis does not just result in left ventricular volume overload, it contributes to myocardial fibrosis of the left ventricle, resulting in left ventricular hypertrophy and left ventricular remodelling. [3] As a result, preoperative cardiac evaluation for patients with AS is now gradually expanding to include cardiac MRI especially in chronic severe AS cases, particularly in the west. [3][4] The only modality of treatment for severe AS is Aortic Valve Replacement (AVR) which is either surgical or transcatheter (Transcatheter Aortic Valve Implantation – TAVI) [5] Early intervention in AS has been shown to be associated with a more favourable outcome as compared with patients in whom LV dysfunction has set in. Aortic valve replacement in AS has been found to be associated with cardiac reverse remodelling, indicated by a reduction in left ventricular dimensions, improvement in left ventricular function, increase in aortic valve area etc. [6] As seen in studies, there is improvement in LV systolic function and reduction in LV mass index that is seen after both surgical as well as transcatheter aortic valve replacement within one year of procedure. [7] It has also been seen that there is an improvement in LV ejection fraction and a reduction in LV mass and postoperative echocardiographic findings have been more strongly found to be associated with prognosis following Aortic Valve Replacement in comparison with preoperative echocardiographic findings. [8]

Furthermore, studies have shown that surgical aortic valve replacement in patients with impaired LV systolic function is associated with a favourable outcome with a 5-year survival rate of more than 70% in the postoperative period, thus implying that AVR must be considered even in patients with depressed LV function. [9] 10-year survival following AVR in patients with low LV function are comparable with survival rates following cardiac transplant, thus suggesting that depressed LV function is not a contraindication to surgical AVR. [10] One situation where cardiac transplantation is associated with a more favourable outcome than AVR in patients with depressed LV function is concomitant coronary artery disease requiring more than 2 grafts. [11]

Postoperative outcomes following AVR in patients with preoperative LV dysfunction also signify beneficial role of surgery. Compensatory mechanics which were lost in patients with severe LV dysfunction were at least partly reversed following AVR and associated with good long-term survival. [12][13]

The purpose of this study was to evaluate the outcomes following AVR in patients with isolated severe Aortic Stenosis with normal and depressed LV function.

SAMPLE SIZE

All patients undergoing Aortic Valve Replacement from September 2022 to September 2024 (24-month period) at Safdarjung Hospital, New Delhi, were identified and records studied.

Those undergoing AVR for Aortic Regurgitation, concomitant CABG or MVR, were excluded from the study.

A total of 15 patients undergoing AVR for isolated severe AS with preoperative LV dysfunction (EF </= 45%) were identified. An equal number (15) who had a preoperative LV function of >50% were randomly chosen. Surgical details were studied, and postoperative echocardiographic paremeters viz. L end systolic and LV end diastolic dimensions and LV ejection fraction were compared with preoperative  findings and compared between the two groups.

INCLUSION CRITERIA

All patients undergoing Aortic Valve Replacement for isolated severe AS and no to moderate Aortic regurgitation. Fifteen patients with normal LV function and fifteen patients with depressed LV function were identified.

EXCLUSION CRITERIA

Associated severe Aortic Regurgitation, concomitant Coronary artery bypass grafting or mitral valve replacement

STATISTICAL ANALYSIS

The data was entered in MS-Excel and STATA 15.0 software was used for statistical analysis. The normality of the data was tested by the Shapiro Wilk test. Descriptive statistics as performed, categorical variables were presented in frequency and percentage and continuous variables were presented as mean ± SD, and minimum-maximum Range. For comparing continuous variables of EF, LVES, LVED with study groups at pre, post and change level, Mann-Whitney test was used. For comparing categorical variables like gender, pathology and expiry with study groups, Chi-square test was used. The test of significance value was taken as <0.05.

As seen in Table 1, there was no statistically significant difference observed in age and gender.

Table 1. Characteristics of the study participants

There was no statistically significant difference observed in AS, AR and AV pathology as seen in Table 2.

Table 2. Pathology

There is a statistically significant difference observed in pre-op and post- op EF (p<0.05). However, no statistically significant difference is observed between the two groups w.r.t. postoperative change in EF as seen in Figure 1 and Table 3. In patients with EF >50% preoperatively, the mean LV function showed a 2% reduction, while in patients with depressed LV function, mean LVEF showed a 3% improvement.

Table 3. Change in LVEF preop and postop

Figure 1. Change in EF (preoperative vs postoperative)

A statistically significant difference was observed in post- op LVES and change (p<0.05) and also between the two groups (normal vs depressed LV function group) as shown in Table 4 and Figure 2. LV end systolic dimensions showed a net reduction of 6.1 mm in patients with normal EF and a reduction by 3.5 mm in patients with low EF. However, there was a definitive overall reduction in LVES dimension in both groups of patients.

Table 4. Change in LVES

Figure 2. (Change in LVES – preoperative vs postoperative)

However, no statistically significant difference existed between the two groups in terms of reduction in LV end diastolic dimension as shown in Table 5 and Figure 2. LV end diastolic dimensions showed a net reduction of 6.7 mm in patients with normal EF and a mean reduction of 6.1 mm in patients with low EF.

Table 5. Change in LVED

Figure 3. (Change in LVED – preoperative vs postoperative)

There was no statistically significant difference observed in expiry of study participants as shown in Table 6.

Table 6. Outcome

The role of AVR in patients with preoperative LV dysfunction has many a time been questioned. The results of this study prove what several other studies have shown – that there is a beneficial role of AVR in patients with preoperative LV dysfunction. As shown in previous studies [14] and proved by the results of this study, Surgical aortic valve replacement is an effective method for treating patients with isolated aortic valve disease and severe LV dysfunction. This procedure is accompanied by satisfactory survival and low risk of serious complications in long-term period.

However, as seen in the study by Spilias N et. al, LV dysfunction is associated with long-term poorer outcome even following successful AVR. [15] In their study, they found that AS causes LV volume overload which in turn results in remodelling of myocytes and eventually LV dysfunction. Data from the Heart Valve Clinic International Database (HAVEC registry) showed that asymptomatic patients with severe AS and LVEF between 50% and 59% had worse outcomes and experienced more HF-related deaths than those with LVEF >60%, even after successful AVR. [15] .

As seen in the study by Helen S. et. al [16] comparing Transcatheter aortic valve replacement with surgical aortic valve replacement, LV dysfunction improved equally after both transcatheter and surgical valve replacement with most improvement occurring within the first 30 days. By 1 year, 53.6% patients with LV dysfunction had normalized their LV function. LVEF remained stable after both TAVR and SAVR in those with preserved LV function. Similar findings were observed in this study, with an improvement in LVEF as well as regression in LV mass to a larger extent occurring in patients with LV dysfunction as compared with those with preserved LV function. The study by Helen S. et. al concluded that in high-risk patients with symptomatic severe AS, baseline LV dysfunction (LVEF, 20%–50%) had no impact on survival after either TAVR or SAVR. Rapid LV functional improvement occurred within 30 days of TAVR and SAVR in most patients. These conclusions were also seen in this study.

The study by Halkos ME et al showed that preoperative LV dysfunction may negatively impact survival in patients with Aortic Stenosis after AVR, in addition to other comorbidities. [17] This was also seen in the study by Furer A et al [19], which concluded that baseline LVEF was an independent predictor of 2-year cardiovascular mortality. In this study, 2 patients in the LV dysfunction group died, but p value is not significant and requires further analysis with a larger subset of population to reach a conclusion regarding the same.

Rabus MB et al in their study concluded that left ventricular ejection fraction and symptoms improve after AVR in patients with isolated severe AS and LVD with an acceptable operative mortality and satisfactory long-term survival [18], a conclusion reached in this study as well.

The study by Elhmidi et al [20] showed that periprocedural mortality rates were similar, however patients with aortic stenosis and severe LV dysfunction exhibit a significantly increased 6-month mortality. Survivors with LV dysfunction, however, show a significant potential for LV function recovery.

LIMITATION

This study’s follow-up period was between 6 months to 2 years. A more comprehensive analysis with detailed and long-term follow-up may yield more data and results regarding the cardiac reverse modelling.

Sample size of 30 patients (15 with LV dysfunction and 15 with normal LV function) warrants detailed and multi-centre study with a large sample size to verify the results of this study.

2 patients (not included) were lost to follow-up. This may compromise the results of the study if conducted on a larger scale with a larger sample size

This study was conducted to determine the outcomes following surgical AVR for isolated severe Aortic Stenosis in patients with normal LV function vis-à-vis patients with LV dysfunction.

As seen in the results, there was no statistically significant difference in mortality, reduction in LV end diastolic dimension and change in LV function in the postoperative period between the two groups. A net reduction in LV end systolic and end diastolic dimensions was observed following AVR in both groups, indicating cardiac reverse modelling and reduction in LV mass index.

In patients with EF >/=45% preoperatively, the mean LV function showed a 2% reduction, while in patients with preoperative LV dysfunction, mean LVEF showed a 3% improvement.

2 patients in the group with low EF expired, however this difference is also statistically insignificant (p = 0.147) and needs analysis of a larger subset of population to reach a conclusion regarding the long-term survival following AVR in patients with heart failure.

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