Ischaemic heart disease (IHD) and chronic obstructive pulmonary disease (COPD) often affect the same patient; in fact, more than one-third of patients with angiography-proven IHD also have COPD on spirometry(1).
A recent study suggests COPD exacerbations in patients with IHD were associated with longer (5 more days) recovery times and suffered more severe breathlessness between exacerbations(2).
An accompanying editorial highlights some important points:

• Patients admitted with COPD exacerbations are more susceptible to myocardial infarction during the admission.

• Infective COPD exacerbations may contribute to heart failure through systemic inflammation, autonomic activation, and increased fluid in the lung. Lung infection can increase ventilation/perfusion mismatch and increased work of breathing, further straining the heart.

• Heart failure can be very difficult to diagnose during a COPD exacerbation because cough, dyspnoea and wheeze are common to both disorders. Physical examination may not be discriminatory, and chest radiography is insensitive to milder degrees of heart failure.

The authors recommed a high index of suspicion combined with consideration of biomarkers (BNP or pro-BNP) and imaging such as echocardiography or even nuclear medicine scans, cardiac MRI, and cardiac catheterisation.
So, next time you’re managing a COPD exacerbation, ask yourself:

• Could there be concomitant heart failure contributing to symptoms?

• If not, is the patient at risk of cardiac events during this admission, for which we need to be vigilant?

• Do I need to consider additional laboratory (BNP) or imaging (echo) investigations? Remember BNP may be elevated in pneumonia and other non-cardiac critical illness, although a normal BNP rules out heart failure.

• Should I add empiric anti-failure therapy to the acute treatment regimen?

• If there is combined COPD exacerbation and heart failure, are there any conflicting priorities in therapy (eg. the pros and cons of beta-agonists, anticholinergics, and steroids)?

1. The complex relationship between ischemic heart disease and COPD exacerbations
Chest. 2012 Apr;141(4):837-8
2. The impact of ischemic heart disease on symptoms, health status, and exacerbations in patients with COPD
Chest. 2012 Apr;141(4):851-7
[EXPAND Click to read abstract]

BACKGROUND: Comorbid ischemic heart disease (IHD) is a common and important cause of morbidity and mortality in patients with COPD. The impact of IHD on COPD in terms of a patient’s health status, exercise capacity, and symptoms is not well understood.

METHODS: We analyzed stable-state data of 386 patients from the London COPD cohort between 1995 and 2009 and prospectively collected exacerbation data in those who had completed symptom diaries for ≥ 1 year.

RESULTS: Sixty-four patients (16.6%) with IHD had significantly worse health status as measured by the St. George Respiratory Questionnaire (56.9 ± 18.5 vs 49.1 ± 19.0, P = .003), and a larger proportion of this group reported more severe breathlessness in the stable state, with a Medical Research Council dyspnea score of ≥ 4 (50.9% vs 35.1%, P = .029). In subsets of the sample, stable patients with COPD with IHD had a higher median (interquartile range [IQR]) serum N-terminal pro-brain natriuretic peptide concentration than those without IHD (38 [15, 107] pg/mL vs 12 [6, 21] pg/mL, P = .004) and a lower exercise capacity (6-min walk distance, 225 ± 89 m vs 317 ± 85 m; P = .002). COPD exacerbations were not more frequent in patients with IHD (median, 1.95 [IQR, 1.20, 3.12] vs 1.86 (IQR, 0.75, 3.96) per year; P = .294), but the median symptom recovery time was 5 days longer (17.0 [IQR, 9.8, 24.2] vs 12.0 [IQR, 8.0, 18.0]; P = .009), resulting in significantly more days per year reporting exacerbation symptoms (median, 35.4 [IQR, 13.4, 60.7] vs 22.2 [IQR, 5.7, 42.6]; P = .028). These findings were replicated in multivariate analyses allowing for age, sex, FEV(1), and exacerbation frequency where applicable.

CONCLUSIONS: Comorbid IHD is associated with worse health status, lower exercise capacity, and more dyspnea in stable patients with COPD as well as with longer exacerbations but not with an increased exacerbation frequency.

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