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Increased risk of coronary artery bypass grafting for left ventricular dysfunction with dilated left ventricle
K Kawachi1, S Kitamura, J Hasegawa
1Department of Surgery III, Nara Medical College, Japan.
Insights
For patients undergoing coronary artery bypass grafting (CABG), elevated left ventricular end-systolic volume (LVESV) and left ventricular end-diastolic volume (LVEDV) indicate higher operative mortality risk, beyond just low ejection fraction (EF).
Area of Science:
- Cardiology
- Cardiac Surgery
- Cardiovascular Imaging
Background:
- Coronary artery bypass grafting (CABG) carries significant operative risks for patients with severe left ventricular dysfunction.
- Low ejection fraction (EF) is a known risk factor for mortality, but its predictive accuracy may be limited.
Purpose of the Study:
- To investigate the correlation between left ventricular volume indices and operative mortality in patients undergoing isolated CABG.
- To determine if left ventricular volumes provide better risk stratification than EF alone for operative mortality.
Main Methods:
- A retrospective analysis of 1000 patients undergoing isolated CABG, categorized by preoperative ejection fraction (EF).
- Detailed analysis of left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV) in relation to hospital mortality.
- Specific focus on 106 patients with EF ≤ 0.4 to assess the impact of elevated ventricular volumes.
Main Results:
- Patients with severe left ventricular dysfunction (EF ≤ 0.3) had significantly higher LVEDV and LVESV compared to those with moderate dysfunction or good function.
- Hospital mortality was 8.0% in the severe dysfunction group (EF ≤ 0.3), higher than the moderate (3.6%) and good function (2.0%) groups.
- In patients with EF ≤ 0.4, mortality was substantially higher (50% for LVESV ≥ 140 ml/m², 67% for LVEDV ≥ 200 ml/m²) compared to those with lower volumes.
Conclusions:
- Elevated left ventricular end-systolic volume (LVESV) and left ventricular end-diastolic volume (LVEDV) are significant predictors of increased hospital mortality following CABG.
- Left ventricular volume indices, in addition to ejection fraction, are crucial for accurate risk assessment in patients undergoing CABG.
Unlabelled:
The operative mortality and morbidity in patients with severe left ventricular dysfunction who undergo coronary artery bypass grafting (CABG) remain high. The low ejection fraction is the major risk factor for operative mortality. However, ejection fraction (EF) alone may not necessarily be an accurate predictor of operative mortality. We studied the correlation between indices of left ventricular volume and operative mortality. One thousand patients undergoing isolated coronary bypass operations were divided into three groups according to their preoperative ejection fraction. Fifty patients (group I) had severe left ventricular dysfunction (EF < or = 0.3), 56 patients (group II) had moderately left ventricular dysfunction (0.3 < EF < or = 0.4) and 894 patients (group III) had good left ventricular function (EF > 0.4). We analyzed the relationship between hospital mortality and left ventricular volume in 106 patients with an EF < or = 0.4.
Results:
Cardiac index was not significantly different among the three groups. The left ventricular end-diastolic pressure (LVEDP) and mean pulmonary artery pressure in groups I an II were higher than those in group III. The left ventricular end-diastolic volume (LVEDV) was 146 +/- 44 ml/m2 in Group I, 112 +/- 31 ml/m2 in Group II and 82 + 30 ml/m2 in Group III, respectively (Group I versus II, p < 0.05, Group I and II versus III, p < 0.01). The left ventricular end-systolic volume (LVESV) was 111 +/- 38 ml/m2 in Group I, 72 +/- 21 ml/m2 in Group II and 30 +/- 14 ml/m2 in Group III, respectively (Group I versus II, p < 0.05, Group I and II versus III, p < 0.01). The LVEDV and LVESV were higher in Group I than in Group II and both in Groups I and II were higher than in Group III. The hospital mortality of any cause before discharge was 8.0% (4/50) in Group I, 3.6% (2/56) in Group II, and 2.0% (18/894) in Group III. The mortality in Group I was higher than that in Group III, but the mortality between Groups I and II was not different. We assessed correlations between large left ventricle with left ventricular dysfunction and operative mortality in 106 patients with ejection fractions of < or = 0.4. The hospital mortality in patients with both under fraction 0.4 and an LVESV > or = 140 ml/m2 was 50% (4/8). This rate was higher than in patients with an LVESV between 80 and 140 ml/m2 (1.8%, 1/55) (p = 0.0006) and an LVESV less than 80 ml/m2 (2.3%, 1/43), (p = 0.0013). The hospital mortality in patients with an LVEDV > or = 200 ml/m2 was 67% (4/6). It was also higher than that in patients with an LVEDV between 200 and 120 ml/m2 (1.7%, 1/58), (p = 0.0001), and an LVEDV less than 120 ml/m2 (2.4%, 1/42), (p = 0.0004). We conclude that patients with a low ejection fraction and an elevated LVESV or LVEDV are at increased risk for hospital death following CABG.