Surgical aortic valve replacement for low-gradient aortic stenosis

AIMS

Low-gradient aortic stenosis is a challenging entity that needs accurate preoperative evaluation. For this high-risk patient population, ad hoc predictive scores are not available and profile risk is currently revealed by the EuroSCOREs. Aims of this study are to verify the suitability of the ES II as predictor of mortality in low-gradient aortic stenosis and to analyse the role of surgery as a treatment.

METHODS

From June 2013 to August 2019, 414 patients underwent surgical aortic valve replacement for low-gradient aortic stenosis. Mean age was 75.78 ± 6.77 years and 190 were women. The prognostic value of Logistic EuroSCORE and EuroSCORE II were compared by receiver-operating characteristics (ROC) curve analysis.

RESULTS

In-hospital, 30-day and 1-year mortality rates were respectively 3.4, 2.9 and 4.8% (14, 12 and 20 patients over 414). In-hospital mortality risk calculated by the Additive EuroSCORE was 7.2 ± 2.7%, by the Logistic EuroSCORE was 9 ± 5.2% and by the ES II was 4.13 ± 2.56%. The prognostic values of the EuroSCORE II and of the EuroSCORE were analysed in a ROC curve analysis for the prediction of in-hospital mortality [area under the curve (AUC): 0.62 vs. 0.58], 30-day mortality (AUC: 0.63 vs. 0.64) and 1-year mortality (AUC: 0.79 vs. 0.65). Both scores did not show significant differences with the only exception of 1-year mortality, for which EuroSCORE II had a better predictive ability than the Logistic EuroSCORE (P < 0.05).

CONCLUSION

In low-gradient aortic stenosis undergoing surgery, the EuroSCORE II is a strong predictor of 1-year mortality.

Low-Gradient aortic stenosis; the diagnostic dilemma

Low-gradient (LG) aortic valve stenosis (AS) constitutes a significant subset among patients with severe aortic stenosis. This entity represents one of the most challenging heart conditions when it comes to diagnosis and management, mainly because of the discrepancy between the small aortic valve area (≤1.0 cm²) that is considered a severe AS, and low mean transvalvular pressure gradient (<40 mmHg), which is one of the criteria for nonsevere AS. LG AS is divided according to transvalvular aortic flow rate into normal-flow LG AS and low-flow LG (LFLG) AS; the latter category can be divided further according to left ventricular ejection fraction (LVEF) into classical LFLG AS if LVEF is depressed or paradoxical LFLG AS if LVEF is preserved. The primary diagnostic challenge in patients with LG AS is to confirm that AS is truly severe and not pseudosevere, which is assessed mainly by either dobutamine stress echocardiography or multidetector computed tomography. The management of symptomatic true severe LG AS is mainly by aortic valve replacement (AVR), whether surgical or transcatheter approach. Patients with LG severe AS have a generally worse prognosis and higher mortality compared with patients with high-gradient severe AS. Despite the survival benefit of AVR in patients with true severe LG AS, these patients have higher surgical risk post-AVR compared with high-gradient AS patients. Early recognition and correct diagnosis of a patient with LG AS is crucial to improve their mortality and morbidity.

Percutaneous versus Surgical Intervention for Severe Aortic Valve Stenosis: A Systematic Review

Aortic stenosis is a disease that is increasing in prevalence and manifests as decreased cardiac output, which if left untreated can result in heart failure and ultimately death. It is primarily a disease of the elderly who often have multiple comorbidities. The advent of transcatheter aortic valve therapies has changed the way we treat these conditions. However, long-term results of these therapies remain uncertain. Recently, there has been an increasing number of studies examining the role of both surgical aortic valve replacement and transcatheter aortic valve replacement. We therefore performed a systematic review using Ovid MEDLINE, Ovid Embase, and the Cochrane Library. Two investigators searched papers published between January 1, 2007, and to date using the following terms: "aortic valve stenosis," "aortic valve operation," and "transcatheter aortic valve therapy." Both strategies in aortic stenosis treatment highlighted specific indications alongside the pitfalls such as structural valve degeneration and valve thrombosis which have a bearing on clinical outcomes. We propose some recommendations to help clinicians in the decision-making process as technological improvements make both surgical and transcatheter therapies viable options for patients with aortic stenosis. Finally, we assess the role of finite element analysis in patient selection for aortic valve replacement. THVT and AVR-S are both useful tools in the armamentarium against aortic stenosis. The decision between the two treatment strategies should be best guided by a strong robust evidence base, ideally with a long-term follow-up. This is best performed by the heart team with the patient as the center of the discussion.

Predicting and measuring mortality risk after transcatheter aortic valve replacement

Introduction: Over the last decade, transcatheter aortic valve replacement (TAVR) has emerged as a treatment option for most patients with severe symptomatic aortic stenosis (AS). With growing indications and exponential increase in the number of TAVR procedures, it is important to be able to accurately predict mortality after TAVR.Areas covered: Herein, we review the surgical and TAVR-specific mortality prediction models (MPMs) and their performance in their original derivation and external validation cohorts. We then discuss the role of other important risk assessment tools such as frailty, echocardiographic parameters, and biomarkers in patients, being considered for TAVR.Expert opinion: Conventional surgical MPMs have suboptimal predictive performance and are mis-calibrated when applied to TAVR populations. Although a number of TAVR-specific MPMs have been developed, their utility is also limited by their modest discriminative ability when applied to populations external to their original derivation cohorts. There is an unmet need for robust TAVR MPMs that accurately predict post TAVR mortality. In the interim, heart teams should utilize the currently available TAVR-specific MPMs in conjunction with other prognostic factors, such as frailty, echocardiographic or computed tomography (CT) imaging parameters, and biomarkers for risk assessment of patients, being considered for TAVR.

Impact of the Trifecta bioprosthetic valve in patients with low-flow severe aortic stenosis

Aortic stenosis (AS) is the most common valve disorder in advanced age. Previous reports have shown that low-flow status of the left ventricle is an independent predictor of cardiovascular mortality after surgery. The Trifecta bioprosthesis has recently shown favorable hemodynamic performance. This study aimed to evaluate the effect of the Trifecta bioprosthesis, which has a large effective orifice area, in patients with low-flow severe AS who have a poor prognosis. We retrospectively evaluated 94 consecutive patients with severe AS who underwent aortic valve replacement (AVR). Patients were divided into two groups according to the stroke volume index (SVI): low-flow (LF) group (SVI < 35 ml/m², n = 22) and normal-flow (NF) group (SVI ≥ 35 ml/m², n = 72). Patients’ characteristics and early and mid-term results were compared between the two groups. There were no differences in patients’ characteristics, except for systolic blood pressure (LF:NF = 120:138 mmHg, p < 0.01) and the rate of atrial fibrillation between the groups. A preoperative echocardiogram showed that the pressure gradient was higher in the NF group than in the LF group, but aortic valve area was similar. The Trifecta bioprosthesis size was similar in both groups. The operative outcomes were not different between the groups. Severe patient–prosthesis mismatch (PPM) (< 0.65 cm²/m²) was not observed in either of the groups. There were no significant differences in mid-term results between the two groups. The favorable hemodynamic performance of the Trifecta bioprosthesis appears to have the similar outcomes in the LF and NF groups. AVR with the Trifecta bioprosthesis should be considered for avoidance of PPM, particularly in AS patients with LV dysfunction.

2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the valvular heart disease guideline provides recommendations for clinicians to diagnose and manage valvular heart disease as well as supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from January 1, 2010, to March 1, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, Cochrane, Agency for Healthcare Research and Quality Reports, and other selected database relevant to this guideline. Structure: Many recommendations from the earlier valvular heart disease guidelines have been updated with new evidence and provides newer options for diagnosis and treatment of valvular heart disease. This summary includes only the recommendations from the full guideline which focus on diagnostic work-up, the timing and choice of surgical and catheter interventions, and recommendations for medical therapy. The reader is referred to the full guideline for graphical flow charts, text, and tables with additional details about the rationale for and implementation of each recommendation, and the evidence tables detailing the data considered in developing these guidelines.

Effects of Aortic Valve Replacement on Severe Aortic Stenosis and Preserved Systolic Function: Systematic Review and Network Meta-analysis

The survival benefits of aortic valve replacement (AVR) in the different flow-gradient states of severe aortic stenosis (AS) is not known. A comprehensive search in PubMed/MEDLINE, Embase, Cochrane Library, CNKI and OpenGrey were conducted to identify studies that investigated the prognosis of severe AS (effective orifice area ≤1.0 cm²) and left ventricular ejection fraction ≥50%. Severe AS was stratified by mean pressure gradient [threshold of 40 mmHg; high-gradient (HG) and low-gradient (LG)] and stroke volume index [threshold of 35 ml/m²; normal-flow (NL) and low-flow (LF)]. Network meta-analysis was conducted to assess all-cause mortality among each AS sub-type with rate ratio (RR) reported. The effects of AVR on prognosis were examined using network meta-regression. In the pooled analysis (15 studies and 9,737 patients), LF states (both HG and LG) were associated with increased mortality rate (LFLG: RR 1.88; 95% CI: 1.43-2.46; LFHG: RR: 1.77; 95% CI: 1.16-2.70) compared to moderate AS; and NF states in both HG and LG had similar prognosis as moderate AS (NFLG: RR 1.11; 95% CI: 0.81-1.53; NFHG: RR 1.16; 95% CI: 0.82-1.64). AVR conferred different survival benefits: it was most effective in NFHG (RR_{with AVR}/RR_{without AVR}: 0.43; 95% CI: 0.22-0.82) and least in LFLG (RR_{with AVR}/RR_{without AVR}: 1.19; 95% CI: 0.74-1.94).

Outcome of isolated aortic valve replacement in patients with classic and paradoxical low-flow, low-gradient aortic stenosis

OBJECTIVE

To analyze operative outcomes and mid-term results after isolated aortic valve replacement (AVR) in low-flow, low-gradient aortic stenosis (LFLG AS) by comparing the 2 subcategories (classic low-flow, low-gradient aortic stenosis [CLFLG] and paradoxical low-flow, low-gradient aortic stenosis [PLFLG]).

METHODS

This was a retrospective analysis of prospectively collected data for all isolated AVR in LFLG AS performed in our center during the last 13 years (n = 198; CLFLG AS, n = 66, 33% and PLFLG AS, n = 132, 67%). Median follow-up was 3.7 ± 3.3 years.

RESULTS

Preoperative mean gradient was 30.2 ± 8.8 mm Hg in the CLFLG AS group and 31.4. ± 7.0 mmHg in the PLFLG AS group (P = .001). Female sex, hypertension, and neurologic and renal disease were more frequent in the PLFLG AS group (P < .01) whereas advanced New York Heart Association class, atrial fibrillation, and pulmonary hypertension were more frequent in the CLFLG AS group (P < .01). In-hospital mortality was 3% in the CLFLG AS group and 2.3% in the PLFLG AS group, P = .08. One- and five-year mortality rates were significantly greater in the CLFLG AS group (27% and 42% vs 6% and 20% in the PLFLG AS group, respectively, P = .001). On follow-up, 90% of the total survivors were in New York Heart Association class I-II, and 51% of the patients in the CLFLG AS group had an improvement in their ventricular function.

CONCLUSIONS

AVR can be performed in LFLG AS with low in-hospital mortality. CLFLG AS carries similar in-hospital mortality to PLFLG AS but greater mid-term mortality. Surgery provided excellent functional status among survivors.

Atrial fibrillation in transcatheter aortic valve implantation patients: Incidence, outcome and predictors of new onset

BACKGROUND

There is controversial evidence if atrial fibrillation (AF) alters outcome after transcatheter aortic valve implantation (TAVI). TAVI itself may promote new-onset AF (NOAF).

METHODS

We performed a single-center study including 398 consecutive patients undergoing TAVI. Before TAVI, patients were divided into a sinus rhythm (SR) group (n=226, 57%) and baseline AF group (n=172, 43%) according to clinical records and electrocardiograms. Furthermore, incidence and predictors of NOAF were recorded.

RESULTS

Baseline AF patients had a significantly higher 1-year mortality than the baseline SR group (19.8% vs. 11.5%, p=0.02). NOAF occurred in 7.1% of patients with prior SR. Previous valve surgery was the only significant predictor of NOAF (HR 5.86 [1.04-32.94], p<0.05). NOAF was associated with higher rehospitalization rate (62.5 vs. 34.8%, p=0.04), whereas mortality was unaffected.

CONCLUSIONS

This study shows that NOAF is associated with higher rates of rehospitalization but not mortality after TAVI. Overall, patients with pre-existing AF have higher mortality.