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Published on: April 21, 2014
Association of Histologic Findings With Long-Term Outcomes in Symptomatic Obstructive Hypertrophic Cardiomyopathy
Shada Jadam1, Andrew Gaballa1, Alaa Alashi1
1Hypertrophic Cardiomyopathy Center, Cleveland Clinic, Cleveland, Ohio, USA.
Insights
In obstructive hypertrophic cardiomyopathy (oHCM) patients, a higher total histology score after surgical myectomy (SM) indicates increased risk of adverse outcomes. This score predicts long-term prognosis in oHCM patients.
Area of Science:
- Cardiology
- Histopathology
- Cardiac Surgery
Background:
- Hypertrophic cardiomyopathy (HCM) is characterized by myocyte hypertrophy, disarray, interstitial fibrosis (IF), and small intramural coronary artery dysplasia (SICAD).
- These histologic findings contribute to left ventricular hypertrophy, diastolic dysfunction, arrhythmogenicity, and microvascular ischemia in HCM patients.
Purpose of the Study:
- To investigate the association between specific histological features and clinical outcomes in patients with obstructive hypertrophic cardiomyopathy (oHCM).
- To evaluate the prognostic value of surgical myectomy (SM) specimen histology in symptomatic oHCM patients.
Main Methods:
- A cohort of 1,722 symptomatic oHCM patients undergoing SM between 2005 and 2018 was analyzed.
- Histologic analysis of SM specimens included grading of myocyte hypertrophy, disarray, IF, and SICAD (0-3 scale), with a total score calculated (0-12).
- Primary endpoint was a composite of death, appropriate defibrillator discharge, or cardiac transplantation during a mean follow-up of 5.1 years.
Main Results:
- Moderate to severe myocyte hypertrophy was observed in 78%, disarray in 14%, IF in 26%, and SICAD in 15% of patients.
- A total histology score greater than 5 was associated with an increased incidence of primary events (25% vs 18%; log-rank P=0.002).
- Multivariable Cox analysis revealed that a total histology score >5 was an independent predictor of adverse long-term outcomes (HR: 1.24; P=0.03).
Conclusions:
- Histologic assessment of SM specimens provides valuable prognostic information in oHCM.
- A higher total histology score is independently associated with adverse long-term outcomes in symptomatic oHCM patients undergoing SM.
Background:
In hypertrophic cardiomyopathy, histologic findings like myocyte hypertrophy and disarray, interstitial fibrosis (IF), and small intramural coronary artery dysplasia (SICAD) result in left ventricular hypertrophy, diastolic dysfunction, arrhythmogenicity, and microvascular ischemia.
Objectives:
The authors sought to evaluate the association between histology and outcomes in obstructive hypertrophic cardiomyopathy (oHCM) patients undergoing surgical myectomy (SM).
Methods:
The study included 1,722 symptomatic oHCM patients (mean age: 56 ± 14 years; 948 [55%] men) who underwent SM at a tertiary center between 2005 and 2018. The SM specimen was analyzed for presence and severity of: 1) myocyte hypertrophy; 2) myocyte disarray; 3) IF; and 4) SICAD. Histologic findings were graded as 0-3 (none, mild, moderate, and severe) and a score from 0-12 was calculated. Primary endpoint was a composite of death, appropriate defibrillator discharge, or cardiac transplantation during follow-up.
Results:
Moderate and severe histologic findings were distributed as follows: myocyte hypertrophy (1,341 [78%]); disarray (237 [14%]); IF (448 [26%]); and SICAD (258 [15%]). The mean total histologic score was 5.1 ± 1.4. At 5.1 ± 5.2 years, there were 352 (20%) primary events (317 [18%] deaths). On spline analysis, a total histology score of >5 was associated with primary events. On Kaplan-Meier analysis, patients with a histology score >5 had greater events vs those with a score ≤5 (147/598 [25%] vs 205/1124 [18%]; log-rank P = 0.002). On multivariable Cox analysis, total histology score >5 (HR: 1.24 [95% CI: 1.03-1.54]; P = 0.03) was independently associated with higher primary events.
Conclusions:
In symptomatic oHCM patients undergoing SM, a higher histologic score was independently associated with long-term outcomes.
