Examining Lack of Referrals to Heart Valve Specialists as Mechanisms of Potential Underutilization of Aortic Valve Replacement

BACKGROUND

Recent studies suggest that Aortic Valve Replacement (AVR) remains underutilized.

AIMS

Investigate the potential role of non-referral to Heart Valve Specialists (HVS) on AVR utilization.

METHODS

Patients with severe aortic stenosis (AS) between 2015 and 2018, who met class I indication for intervention, were identified. Baseline data and process-related parameters were collected to analyze referral predictors and evaluate outcomes.

RESULTS

Among 981 patients meeting criteria AVR, 790 patients (80.5%) were assessed by HVS within six months of index TTE. Factors linked to reduced referral included increasing age (OR: 0.95; 95% CI: 0.94 - 0.97; P <0.001), unmarried status (OR: 0.59; 95% CI: 0.43 - 0.83; P =0.002) and inpatient TTE (OR: 0.27; 95% CI: 0.19 - 0.38; P <0.001). Conversely, higher hematocrit (OR: 1.13; 95% CI: 1.09 - 1.16; P <0.001) and eGFR (OR: 1.01; 95% CI: 1.00 - 1.02; P =0.003), mean aortic valve gradient (OR: 1.03; 95% CI: 1.01 - 1.04; P <0.001) and preserved LVEF (OR: 1.59; 95% CI: 1.02 - 2.48; P =0.04), were associated with increased referral likelihood. Moreover, patients assessed by HVS referral as a time-dependent covariate had a significantly lower two-year mortality risk than those who were not (aHR: 0.30; 95% CI: 0.23- 0.39; P < 0.001).

CONCLUSION

A substantial proportion of severe AS patients meeting indications for AVR are not evaluated by HVS and experience markedly increased mortality. Further research is warranted to assess the efficacy of care delivery mechanisms, such as e-consults, and telemedicine, to improve access to HVS expertise.

Trends in Utilization of Aortic Valve Replacement for Severe Aortic Stenosis

BACKGROUND

Despite the rapid growth of aortic valve replacement (AVR) for aortic stenosis (AS), limited data suggest symptomatic severe AS remains undertreated.

OBJECTIVES

This study sought to investigate temporal trends in AVR utilization among patients with a clinical indication for AVR.

METHODS

Patients with severe AS (aortic valve area <1 cm²) on transthoracic echocardiograms from 2000 to 2017 at 2 large academic medical centers were classified based on clinical guideline indications for AVR and divided into 4 AS subgroups: high gradient with normal left ventricular ejection fraction (LVEF) (HG-NEF), high gradient with low LVEF (HG-LEF), low gradient with normal LVEF (LG-NEF), and low gradient with low LVEF (LG-LEF). Utilization of AVR was examined and predictors identified.

RESULTS

Of 10,795 patients, 6,150 (57%) had an indication or potential indication for AVR, of whom 2,977 (48%) received AVR. The frequency of AVR varied by AS subtype with LG groups less likely to receive an AVR (HG-NEF: 70%, HG-LEF: 53%, LG-NEF: 32%, LG-LEF: 38%, P < 0.001). AVR volumes grew over the 18-year study period but were paralleled by comparable growth in the number of patients with an indication for AVR. In patients with a Class I indication, younger age, coronary artery disease, smoking history, higher hematocrit, outpatient index transthoracic echocardiogram, and LVEF ≥0.5 were independently associated with an increased likelihood of receiving an AVR. AVR was associated with improved survival in each AS-subgroup.

CONCLUSIONS

Over an 18-year period, the proportion of patients with an indication for AVR who did not receive AVR has remained substantial despite the rapid growth of AVR volumes.

Subclinical Burden of Coronary Artery Calcium in Patients With Coarctation of the Aorta

Coronary computed tomography (CT) angiography is often performed in adults with coarctation of the aorta (CoA) for anatomic assessment. As this population ages, assessment of atherosclerotic cardiovascular disease burden is important. Thus, quantitative and qualitative coronary artery calcium (CAC) scores were assessed for patients with CoA ≥16 years of age, who were seen at a referral center. CoA patients had either coronary CT angiography or chest CT with interpretable coronary information performed for clinical indications (follow-up, preoperative, or for symptoms) from 2004 to 2017. Qualitative CAC was determined based on low-dose CT and lung cancer screening protocols. Quantitative CAC scores were compared with an age- and gender-matched control cohort of patients chosen from an emergency department database of patients who received coronary CT angiography for chest pain evaluation. Atherosclerotic cardiovascular disease 10-year predicted risk scores were calculated for both cohorts. Out of 131 patients with CoA (mean age 46.1 ± 15.3 years), 22 patients (17%) had multivessel atherosclerotic disease on qualitative assessment. In the subgroup of patients ≥40 years, those with CoA were more likely to have a quantitative CAC score ≥400 compared with those without CoA (14% vs 4%, p = 0.02). Median atherosclerotic cardiovascular disease risk score was 8% (interquartile range 2% to 12%) for CoA patients ≥40 years, and 5% (interquartile range 2% to 9%) for patient without CoA ≥40 years. In conclusion, we determined that CoA patients have subclinical atherosclerosis identifiable on CT in high rates when compared with patients without CoA. Atherosclerotic cardiovascular disease should be assessed in these patients for prevention and treatment.

Frequency of Guideline-Based Statin Therapy in Adults With Congenital Heart Disease

We aimed to evaluate atherosclerotic cardiovascular disease (ASCVD) risk estimates and guideline-based statin use for primary prevention of ASCVD in adults with congenital heart disease (ACHD). This was a case-controlled, retrospective study of 248 cases and 744 age- and gender-matched controls at a tertiary care referral center. ASCVD risk scores were calculated and used to assess indication for statin treatment for primary prevention per the 2013 American College of Cardiology and American Heart Association guideline on assessment of cardiovascular risk. There were no differences in average 10-year ASCVD risk scores between ACHD cases (4.6% ± 6.6%) and matched controls (5.1% ± 6.7%, p = 0.32). ACHD cases had lower total cholesterol (183 ± 38 vs 192.6 ± 35.3 mg/dL, p < 0.001) and were less likely to smoke (8.1% vs 14.6%, p = 0.008), yet had lower high density lipoprotein (52.6 ± 17.2 vs 55.3 ± 17.1 mg/dL, p = 0.03) and higher hypertension rates (38.7% vs 28.5%, p = 0.003). However, only 42.3% ACHD cases with a primary prevention statin indication were appropriately prescribed therapy as compared with 59.0% of controls (p = 0.04). In conclusion, ACHD cases have a similar 10-year ASCVD risk score than age- and gender-matched peers, but ACHD cases are less likely than their peers to be prescribed statin therapy for primary prevention per guideline-based recommendations.

Transseptal mitral valve replacement after transcatheter aortic valve implantation

We report a case of mitral valve replacement in a patient who had previously undergone transcatheter aortic valve implantation. A transseptal approach was used to avoid displacing the aortic prosthesis. Because of the small mitral annulus, a bioprosthetic aortic valve was used in reverse position for mitral valve replacement. The procedure did not interfere with the existing prosthesis, and a follow-up echocardiogram showed that both prosthetic valves were functioning well.To the best of our knowledge, this is the first report of mitral valve replacement in a patient who had a preceding transcatheter aortic valve implantation. We believe that the transseptal approach is promising for mitral valve replacement in such patients. Moreover, using a bioprosthetic aortic valve in reverse position is an option for mitral valve replacement when the mitral annulus is too small for placement of a standard bioprosthetic mitral valve.