Prediction of thrombo‐embolic risk in patients with hypertrophic cardiomyopathy (HCM Risk‐CVA)

Abstract

AimsAtrial fibrillation (AF) and thrombo‐embolism (TE) are associated with reduced survival in hypertrophic cardiomyopathy (HCM), but the absolute risk of TE in patients with and without AF is unclear. The primary aim of this study was to derive and validate a model for estimating the risk of TE in HCM. Exploratory analyses were performed to determine predictors of TE, the performance of the CHA2DS2‐VASc score, and outcome with vitamin K antagonists (VKAs).Methods and resultsA retrospective, longitudinal cohort of seven institutions was used to develop multivariable Cox regression models fitted with pre‐selected predictors. Bootstrapping was used for validation. Of 4821 HCM patients recruited between 1986 and 2008, 172 (3.6%) reached the primary endpoint of cerebrovascular accident (CVA), transient ischaemic attack (TIA), or systemic peripheral embolus within 10 years. A total of 27.5% of patients had a CHA2DS2‐VASc score of 0, of whom 9.8% developed TE during follow‐up. Cox regression revealed an association between TE and age, AF, the interaction between age and AF, TE prior to first evaluation, NYHA class, left atrial (LA) diameter, vascular disease, and maximal LV wall thickness. There was a curvilinear relationship between LA size and TE risk. The model predicted TE with a C‐index of 0.75 [95% confidence interval (CI) 0.70–0.80] and the D‐statistic was 1.30 (95% CI 1.05–1.56). VKA treatment was associated with a 54.8% (95% CI 31–97%, P = 0.037) relative risk reduction in HCM patients with AF.ConclusionsThe study shows that the risk of TE in HCM patients can be identified using a small number of simple clinical features. LA size, in particular, should be monitored closely, and the assessment and treatment of conventional vascular risk factors should be routine practice in older patients. Exploratory analyses show for the first time evidence for a reduction of TE with VKA treatment. The CHA2DS2‐VASc score does not appear to correlate well with the clinical outcome in patients with HCM and should not be used to assess TE risk in this population.

Direct oral anticoagulants in patients with hypertrophic cardiomyopathy and atrial fibrillation

“…LA diameter was greater in subjects who had thromboembolic events, which is also consistent with previous studies 9,22 . The present study also supports recent ESC guidelines that advise against CHA 2 DS 2 -VASc score use in HCM with AF, as the group of patients who suffered thromboembolic events did not present a higher prevalence of vascular risk factors such as hypertension or diabetes 3 .…”

Predictors of atrial fibrillation in hypertrophic cardiomyopathy

“…The findings in this and our previous study on stroke in HCM6 suggest that patients with risk factors for AF should undergo frequent ambulatory ECG monitoring to detect atrial arrhythmia and could be considered for early prophylactic anticoagulation. The identification of associations with common cardiovascular risk factors such as vascular disease and hypertension is not by itself that surprising but shows that management of these risk factors should be given equal priority to other disease-specific complications.…”

“…The study cohort has been described in detail in a previous manuscript on thromboembolism in HCM (HCM Risk-CVA) 6. Subgroups of patients from this cohort have been reported in other recently published studies (see online supplementary table S1).…”

“…All patients underwent pedigree analysis, clinical assessment, physical examination, resting and ambulatory ECG and transthoracic echocardiography as previously described 6. Each participating centre collected data independently.…”

“…In order to prevent AF and its sequelae, it is necessary to develop methods for stratifying patients into subgroups that will derive most benefit from targeted therapeutic strategies. In a recent multicentre study (HCM Risk-CVA) we demonstrated that patients at high risk of thromboembolic stroke can be identified using a small number of simple clinical parameters including a history of AF 6. The primary aim of this study was to determine predictors of new onset AF in the same cohort.…”