Early effects of transcatheter aortic valve replacement on cardiac sympathetic nervous function assessed by 123I-metaiodobenzylguanidine scintigraphy in patients with severe aortic valve stenosis

Cardiac Sympathetic Nerve Function in Patients with Severe Aortic Stenosis Prior and After Transcatheter Aortic Valve Implantation: Evaluation by 5-Year Risk Model

Background: While the non-invasive assessment of cardiac sympathetic nerve dysfunction is readily accessible, its applicability in invasive intervention for structural heart disease has received limited investigation. Our study aimed to clarify the cardiac sympathetic nerve function in patients with severe Aortic stenosis (AS) and its postoperative changes after transcatheter aortic valve implantation (TAVI) using 123I-metaiodobenzylguanidine scintigraphy (MIBG) in combination with 5-year mortality prediction model. Methods: Consecutive 26 patients (83±5ys, male 4) with severe AS who underwent MIBG prior TAVI procedures were retrospectively enrolled. Of those, 15 patients underwent postoperative-follow up MIBG. The early and delayed heart-to-mediastinum ratio (e- and d-H/M), and washout rate (WR) were obtained from MIBG planner imaging. The MIBG 5-year mortality prediction model was employed to compare pre and after TAVI. Cardiac function and wall thickness were evaluated with transthoracic echocardiography. Results: Preoperative e-H/M, d-H/M, and WR were 2.4±0.5, 2.3±0.4, and 29±14% respectively, and WR showed significant correlation to left ventricular ejection fraction (LVEF) and brain natriuretic peptide (BNP) (r=-0.4 and 0.6; p=0.03, and 0.001 for LVEF and BNP, respectively). 102±28 days after TAVI, either H/M or WR did not show significant improvement among enrolled patients (2.5±0.3, 2.3±0.4, and 30±11% for e-, d-H/M, and WR for after TAVI), while the BNP level was significantly reduced (128±691 and 94±194 pg/dl, for pre vs. after, p=0.008). Five patients showed a significant recovery in WR (37.0±13.8 and 28.8±8.5% for pre and post, p=0.04), and left ventricular wall thickness was significantly thinner compared to those who did not recover (15.2±3.2 vs 11.2±2.4, p=0.02; 14.2±2.9 vs 10.8±1.8, p=0.02 for intraventricular septum and posterior wall, respectively). In 5-year prediction risk model, 7 patients showed a significant reduction in mortality risk, and the patients who did not show risk reduction had significantly reduced renal function (eGFR 57.5±18.8 vs. 38.2±11.3 ml/min/1.73m2, p=0.03 for recovered vs. not recovered). Conclusion: After a 3-month follow-up after TAVI, diverse response in cardiac MIBG parameters were observed among patients with severe AS, despite successful valve replacement. Cardiac MIBG serves as a non-invasive tool that can comprehensively evaluate and surrogate the severity of heart failure resulting from a multi-factorial condition.

Impact of surgical aortic valve replacement and transcatheter aortic valve implantation on cardiovascular and cerebrovascular controls: A pilot study

Surgical aortic valve replacement (SAVR) and transcatheter aortic valve implantation (TAVI) are options in severe aortic valve stenosis (AVS). Cardiovascular (CV) and cerebrovascular (CBV) control markers, derived from variability of heart period, systolic arterial pressure, mean cerebral blood velocity and mean arterial pressure, were acquired in 19 AVS patients (age: 76.8 ± 3.1 yrs, eight males) scheduled for SAVR and in 19 AVS patients (age: 79.9 + 6.5 yrs, 11 males) scheduled for TAVI before (PRE) and after intervention (POST, <7 days). Left ventricular function was preserved in both groups. Patients were studied at supine resting (REST) and during active standing (STAND). We found that: (i) both SAVR and TAVI groups featured a weak pre-procedure CV control; (ii) TAVI ensured better CV control; (iii) cerebral autoregulation was working in PRE in both SAVR and TAVI groups; (iv) SAVR and TAVI had no impact on the CBV control; (v) regardless of group, CV and CBV control markers were not influenced by STAND in POST. Even though the post-procedure preservation of both CV and CBV controls in TAVI group might lead to privilege this procedure in patients at higher risk, the missing response to STAND suggests that this advantage could be insignificant.

Left ventricular hypertrophy as a predictor of cardiovascular outcomes after transcatheter aortic valve replacement

AIMS

This study aimed to clarify the relationship between cardiovascular prognosis and left ventricular hypertrophy (LVH) in patients with severe aortic stenosis who underwent transcatheter aortic valve replacement (TAVR) and to investigate the relationship between cardiac sympathetic nerve (CSN) function and these factors using 123 I-metaiodobenzylguanidine scintigraphy.

METHODS AND RESULTS

In this single-centre, retrospective observational study, 349 patients who underwent TAVR at our institution between July 2017 and May 2020 were divided into two groups: those with severe LVH pre-operatively [severe LVH (+) group] and those without LVH pre-operatively [severe LVH (-) group]. The rates of freedom from cardiovascular events (cardiovascular death and heart failure hospitalization) were compared. The relationship between changes in left ventricular mass index (LVMi) and changes in delay heart-mediastinum ratio (H/M) from before TAVR to 6 months after TAVR was also investigated. The event-free rate was significantly lower in the severe LVH (+) group (87.1% vs. 96.0%, log-rank P = 0.021). The severe LVH (+) group exhibited a significantly lower delay H/M value, scored by 123 I-metaiodobenzylguanidine scintigraphy, than the severe LVH (-) group (2.33 [1.92-2.67] vs. 2.67 [2.17-3.68], respectively, P < 0.001). Moreover, the event-free rate of post-operative cardiovascular events was lower among patients with a delay H/M value < 2.50 than that among other patients (87.7% vs. 97.2%, log-rank P = 0.012). LVMi was significantly higher (115 [99-130] vs. 90 [78-111] g/m2 , P < 0.001) and delay H/M value was significantly lower (2.53 [1.98-2.83] vs. 2.71 [2.25-3.19], P = 0.025) in the severe LVH (+) group than in the severe LVH (-) group at 6 months after TAVR. Patients with improved LVH at 6 months after TAVR also had increased delay H/M (from 2.51 [2.01-2.81] to 2.67 [2.26-3.02], P < 0.001), whereas those without improved LVH had no significant change in delay H/M (from 2.64 [2.23-3.06] to 2.53 [1.97-3.00], P = 0.829).

CONCLUSIONS

Severe LVH before TAVR is a prognostic factor for poor post-operative cardiovascular outcomes. LVH associated with aortic stenosis and CSN function are correlated, suggesting their involvement in LVH prognosis.

Left-atrial volume reduction reflects improvement of cardiac sympathetic nervous function in patients with severe aortic stenosis after transcatheter aortic valve replacement

Trans-catheter aortic valve replacement (TAVR) is an excellent alternative intervention for surgical aortic valve replacement. Cardiac sympathetic nervous (CSN) function and left atrial (LA) volume are both important prognostic factors in patients with aortic stenosis (AS) after TAVR. The relationship between the two clinical factors is unknown, however. This retrospective observational study aimed to assess the correlation between CSN function and LA volume in 48 symptomatic patients with severe AS (median age: 85 years, IQR 82-88 years; 81% female) before and after TAVR. CSN function was assessed by performing ¹²³I-metaiodobenzylguanidine (MIBG) scintigraphy before and 6 months after TAVR, and the delayed heart-to-mediastinum ratio (dHMR) and washout rate (WR) were calculated. We also performed transthoracic echocardiography near the same time. TAVR improved the dHMR, WR, and LA volume index (LAVI) (dHMR: median 2.89 [IQR 2.62-3.23] vs. 2.98 [2.49-3.25], p = 0.0182; WR: 28% [24-38] vs. 23% [16-32], p < 0.0001; LAVI: 47.7 mL/m² [37.8-56.3] vs. 41.2 mL/m² [33.7-56.1], p = 0.0024). In multiple linear regression analysis, the percentage change in LAVI from baseline to post-TAVR (∆LAVI%) was an independent predictor of change in dHMR from baseline to post-TAVR (β =  - 0.35, p = 0.0110). In conclusion, LA volume reduction reflected CSN functional improvement after TAVR. In patients with TAVR, ∆LAVI% might be a valuable parameter for evaluating CSN functional recovery.

Serial changes in cardiac sympathetic nervous function after transcatheter aortic valve replacement: A prospective observational study using 123I-meta-iodobenzylguanidine imaging

BACKGROUND

Transcatheter aortic valve replacement (TAVR) can rapidly improve cardiac sympathetic nervous function (CSNF) within 2 weeks in patients with aortic stenosis (AS). However, whether such short-term improvements will be sustained thereafter remains unclear.

METHODS

Patients with severe AS who underwent TAVR between October 2017 and June 2019 were enrolled in this single-center, prospective, observational study. 123I-meta-iodobenzylguanidine imaging was performed at baseline, within 2 weeks after TAVR, and at 6 to 12 months post-TAVR to evaluate the heart-mediastinum ratio (H/M) and washout rate.

RESULTS

Of 183 consecutive patients, 75 (19 men; median age: 86 years) were evaluated. The late H/M significantly improved within 2 weeks after TAVR (P = .041) and further improved over 6 to 12 months after TAVR (P = .041). Multivariate analysis revealed that the baseline mean aortic valve pressure gradient (mPG) was an independent predictor of mid-term improvement in the late H/M (> 0.1) (P = .037). Patients with a high baseline mPG (≥ 58 mmHg) exhibited a significantly greater increase in the late H/M than those with a low baseline mPG (< 42 mmHg) (0.24 vs 0.01; P = .029).

CONCLUSION

CSNF demonstrated sustained improvement from within 2 weeks after TAVR until 6 to 12 months later. Such improvement was related to baseline hemodynamic AS severity.

Factors Influencing Cardiac Sympathetic Nervous Function in Patients With Severe Aortic Stenosis: Assessment by 123I-Metaiodobenzylguanidine Myocardial Scintigraphy

BACKGROUND

Numerous studies have shown that 123I-metaiodobenzylguanidine (MIBG) scintigraphy, an index of cardiac sympathetic nervous (CSN) activity, is useful for predicting prognosis in patients with heart failure. However, the factors influencing the CSN activity of patients with severe aortic stenosis (AS) remain unclear.

METHODS

We enrolled 91 patients with severe AS who underwent 123I-MIBG scintigraphy, coronary computed tomography (CCT), and transthoracic echocardiography. When CCT angiography (CCTA) showed an obstructive epicardial artery, invasive coronary angiography was performed within 1 week of CCTA.

RESULTS

There were 21 male and 70 female patients with a mean age of 84±5 years. Eighty-five (85) patients (93%) had hypertension and 13 patients (14%) had diabetes. Two (2) patients (2%) had previous myocardial infarction and eight (9%) had a previous coronary intervention. All patients had severe AS: aortic valve area was 0.63±0.18 cm² and the mean pressure gradient was 56±19 mmHg. Regarding 123I-MIBG parameters, early heart-to-mediastinum (H/M) ratio was 3.1±0.5, delayed H/M ratio was 2.8±0.6, and the washout rate (WR) was 35%±13%. Multivariable linear regression analysis showed that coronary artery disease (β=-0.30, p=0.002) was an independent predictor of delayed H/M ratio, and that aortic valve area (β=-0.20, p=0.048) was an independent predictor of WR.

CONCLUSIONS

Our findings suggest that coronary artery disease is an independent predictor of delayed H/M ratio, and aortic valve area is an independent predictor of WR in patients with severe AS.

Antithrombotic therapy in patients undergoing transcatheter aortic valve replacement: the complexity of the elderly

Along with epidemiologic transitions of the global population, the burden of aortic stenosis (AS) is rapidly increasing and transcatheter aortic valve replacement (TAVR) has quickly spread; indeed, it is nowadays also employed in treating patients with AS at intermediate operative risk. Nonetheless, the less invasive interventional strategy still carries relevant issues concerning post-procedural optimal antithrombotic strategy, given the current indications provided by guidelines are not completely supported by evidence-based data. Geriatric patients suffer from high bleeding and thromboembolic risks, whose balance is particularly subtle due to the presence of concomitant conditions, such as atrial fibrillation and chronic kidney disease, that make the post-TAVR antithrombotic management particularly insidious. This scenario is further complicated by the lack of specific evidence regarding the 'real-life' complex conditions typical of the geriatric syndromes, thus, the management of such a heterogeneous population, ranging from healthy ageing to frailty, is far from being defined. The aim of the present review is to summarize the critical points and the most updated evidence regarding the post-TAVR antithrombotic approach in the geriatric population, with a specific focus on the most frequent clinical settings.

Prognostic value of cardiac 123 I-metaiodobenzylguanidine imaging for predicting cardiac events after transcatheter aortic valve replacement

Aims

In patients with aortic valve stenosis (AS), cardiac sympathetic nervous (CSN) dysfunction and its improvement after transcatheter aortic valve replacement (TAVR) have been reported. The prognostic impact of CSN function remains unclear. This study investigated the prognostic value of cardiac ¹²³I‐metaiodobenzylguanidine (MIBG) imaging for predicting cardiac events after TAVR.

Methods and results

This single‐centre prospective observational study enrolled patients with AS between July 2017 and May 2019. MIBG scintigraphy was performed before and soon after TAVR to evaluate the late heart–mediastinum ratio (L‐H/M). Patients were classified into three pairs of groups based on the baseline and post‐TAVR L‐H/M (≥2.0 or <2.0) and on the presence of TAVR‐related improvement in L‐H/M. The study endpoint was the occurrence of major adverse cardiac events (MACE), defined as a composite of all‐cause death, non‐fatal myocardial infarction, and hospitalization due to heart failure. Among the 187 consecutive patients who underwent TAVR, 107 (27 men; median age: 86 years) were evaluated. Over a median follow‐up of 366 days, 15 (14.0%) patients had MACE. The incidence of MACE was significantly low in patients with L‐H/M improvement and/or high post‐TAVR L‐H/M (≥2.0). Baseline L‐H/M and frailty were associated with poor response of L‐H/M to TAVR treatment. TAVR‐related improvement in L‐H/M had significant effects on MACE, with an adjusted hazard ratio of 0.233 (95% confidence interval, 0.064–0.856; P = 0.028).

Conclusions

TAVR‐related improvement in L‐H/M was an independent predictor of cardiac events, 1 year after TAVR. Cardiac MIBG imaging is useful for predicting cardiac events after TAVR.

Impact of Prosthesis-Patient Mismatch After Transcatheter Aortic Valve Replacement on Changes in Cardiac Sympathetic Nervous Function

The impact of prosthesis-patient mismatch (PPM) after transcatheter aortic valve replacement (TAVR) on changes in cardiac sympathetic nervous (CSN) function remains unclear. Using 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy, we investigated the impact of PPM after TAVR on CSN activity.We enrolled 44 of 117 patients with severe aortic stenosis who underwent TAVR for analysis in the present study. We conducted 123I-MIBG scintigraphy at baseline and at about 9 months after TAVR. Differences between baseline and post-TAVR 123I-MIBG parameters were compared between cases with and without PPM.There were 17 and 27 patients with and without PPM, respectively. Those without PPM exhibited significantly decreased left ventricular mass index (122 ± 36 g/m² versus 108 ± 30 g/m², P < 0.001) following TAVR, whereas those with PPM did not (117 ± 21 g/m² versus 110 ± 17 g/m², P = 0.09). Significant improvements in delayed heart-to-mediastinum (H/M) ratio (2.8 ± 0.4 versus 3.0 ± 0.4, P = 0.004) and washout rate (WR) (33% ± 10% versus 24% ± 12%, P < 0.001) were observed after TAVR in patients without PPM but not in those with PPM. Multivariable linear regression analysis revealed PPM to be a negative predictor of improvements in delayed H/M ratio and WR.Delayed H/M ratio and WR improve significantly after TAVR in the absence of PPM, whereas these improvements are not observed in patients with PPM. Hence, the presence of PPM is a negative predictor of improvements in delayed H/M ratio and WR in patients undergoing TAVR.