Non ECG gated supine to prone left ventricular volume ratio: a novel marker for myocardial ischemia
Min Sen Yew1, Wei Sheng Jonathan Ong2, See Jin Jesse Ong2
1Department of Cardiology, Tan Tock Seng Hospital, 11 Jln Tan Tock Seng, Singapore, 308433, Singapore. Min_sen_yew@ttsh.com.sg.
Insights
Transient ischemic dilation (TID) indicates severe coronary artery disease (CAD). The supine to prone left ventricular (LV) volume ratio (SPLVr) may help identify severe CAD in TID patients, showing lower values in those with the condition.
Area of Science:
- Cardiology
- Nuclear Medicine
- Radiology
Background:
- Transient ischemic dilation (TID) is a marker of severe coronary artery disease (CAD).
- Prone positioning typically reduces left ventricular (LV) volume in healthy individuals.
- This physiological response may be altered in patients with severe CAD due to worsened cardiac hemodynamics when prone.
Purpose of the Study:
- To evaluate the utility of the non-ECG gated supine to prone LV volume ratio (SPLVr) for identifying severe CAD.
- To investigate the correlation between SPLVr and the extent of perfusion abnormalities in patients with TID.
Main Methods:
- Retrospective analysis of 130 patients with TID ratio ≥ 1.21 and available supine and prone SPECT images.
- Calculation of SPLVr as the post-stress supine to prone LV volume ratio.
- Correlation analysis of SPLVr with summed stress and rest scores and assessment of its predictive value for severe CAD using coronary angiography data.
Main Results:
- SPLVr showed a significant negative correlation with summed stress (r = -0.221, p = 0.011) and rest scores (r = -0.292, p = 0.001).
- Patients with severe CAD (n=52) had a significantly lower mean SPLVr (1.05 ± 0.14) compared to those without (1.12 ± 0.17, p = 0.012).
- SPLVr predicted severe CAD on univariate analysis (OR 0.12, p = 0.01) but not in multivariate analysis.
Conclusions:
- SPLVr is a novel marker that negatively correlates with the extent of perfusion abnormalities.
- SPLVr is lower in patients with TID and severe CAD.
- Further research is needed to confirm SPLVr's reliability in identifying severe CAD among TID cases.
Abstract:
Transient ischemic dilation (TID), a marker of severe coronary artery disease (CAD), is the post-stress to rest left ventricular (LV) volume ratio quantified using non ECG gated single photon emission computerized tomography (SPECT). Although prone positioning causes physiological reduction of LV volume in normal subjects, we hypothesize this may not occur in TID with underlying severe CAD as cardiac hemodynamics worsen when prone. We aim to evaluate the utility of the non ECG gated supine to prone LV volume ratio (SPLVr) for identifying severe CAD. Retrospective data analysis from 130 patients with TID ratio ≥ 1.21 and both post-stress supine and prone images. SPLVr had a significant negative correlation with summed stress (r = - 0.221, p = 0.011) and rest (r = - 0.292, p = 0.001) scores. Of the 129 cases with follow-up invasive or computed tomography coronary angiography, 52 (40.3%) had severe CAD (left main ≥ 50% stenosis, 3-vessel with ≥ 70% stenosis or 2-vessel with proximal left anterior descending ≥ 70% stenosis). Mean SPLVr was significantly lower in severe CAD cases (1.05 ± 0.14 vs 1.12 ± 0.17, p = 0.012). SPLVr predicted severe CAD on univariate [OR 0.12 (95% CI 0.00-0.35) p = 0.01] but not in multivariate analysis. SPLVr is a novel marker that negatively correlates with extent of perfusion abnormalities and is lower amongst TID patients with severe CAD. Larger studies are needed to assess if SPLVr can reliably identify underlying severe CAD amongst TID cases.
