Utility of radiographic measurements to predict echocardiographic left heart enlargement in dogs with preclinical myxomatous mitral valve disease

Abstract

Background: Evaluation of left heart size helps determine disease severity in dogs with myxomatous mitral valve disease (MMVD). Hypothesis/Objectives: Determine the ability of radiographic vertebral heart size (VHS) and vertebral left atrial size (VLAS) to predict LHE ECHO in dogs with preclinical MMVD. Animals: Seventy client-owned dogs with MMVD and no historical or present clinical or radiographic evidence of congestive heart failure (CHF). Methods: Retrospective cross-sectional study of dogs with same-day echocardiography and thoracic radiography. Receiver-operating characteristic (ROC) curves were used to assess the ability of VHS, VLAS, and VHS + VLAS to discern dogs with and without LHE ECHO , and clinically relevant cutpoints for these radiographic measurements were selected. Results: The ability of VHS and VHS + VLAS to predict LHE ECHO was moderate (area under the curve [AUC] VHS = 0.851; 95% CI, 0.762-0.941; AUC VHS + VLAS = 0.865; 0.783-0.947), and performance of VLAS and VHS + VLAS was not different from that of VHS alone. A VHS cutpoint of >10.8 had sensitivity = 91.1% (76.3%-98.1%) and specificity = 69.4% (51.9%-83.7%) for predicting LHE ECHO. A cutpoint of >11.7 had sensitivity = 32.4% (17.4%-50.5%) and specificity = 97.2% (85.5%-99.9%) for predicting LHE ECHO. Thirty (43%) of the 70 dogs had a VHS value of 10.9 to 11.7. Conclusions and Clinical Importance: Vertebral heart size >11.7 identified dogs with LHE ECHO and VHS ≤ 10.8 excluded dogs with LHE ECHO. A large percentage of dogs had VHS values intermediate to these cutpoints.

Radiographic quantification of left atrial size in dogs with myxomatous mitral valve disease

“…The results of this study have reinforced the previously described 24,25,34‐36 positive correlation between VLAS and LA/Ao ( r = 0.76, 95% CI 0.64‐0.85, P < .001). The optimal cut‐off value of ≥2.4 vertebrae derived from ROC analyzis in the current study to identify a LA/Ao ≥1.6 was close to the cut‐off value of ≥2.3 vertebrae originally proposed, 25 and the cut‐off value of ≥2.5 vertebrae reported subsequently 34,36 .…”

Evaluation of radiographic predictors of left heart enlargement in dogs with known or suspected cardiovascular disease

“…The reason for this discrepancy is unclear. Based on the results of our study and others, [2][3][4][5] we believe it is reasonable to conclude that both VLAS and VHS are clinically useful for clinical staging of dogs with known or highly suspected subclinical MMVD. Vertebral heart size >11.7-12.25 suggest EchoB2 is very likely.…”

“…Vertebral heart size >11.7-12.25 suggest EchoB2 is very likely. 3,5 This study has limitations that should be acknowledged. Both VLAS and VHS have inherent limitations and they can be challenging to measure in some scenarios.…”

“…where left heart size (by radiography or echocardiography) is useful for clinical staging, [1][2][3][4][5] predicting risk for heart failure, [6][7][8] aiding treatment decisions in the subclinical stage (ACVIM stage B), [9][10][11] and estimating prognosis. 9,[12][13][14][15][16][17] Relative to thoracic radiography, echocardiography represents the clinical reference standard for assessment of cardiac chamber size.…”

“…[2][3][4] A recent study has suggested VHS is more clinically useful compared to VLAS to identify echocardiographic left heart enlargement in dogs with MMVD. 5 In contrast to VHS, there is limited knowledge regarding the clinical utility of VLAS beyond the context of MMVD. It would be advantageous to assess the diagnostic accuracy of VLAS for detecting LA enlargement within a variety of diseases and clinical contexts confirmed by echocardiography.…”