Impact of advanced imaging techniques on cardiac surgery-New insights provided by cardiac magnetic resonance.

This dialog between a cardiac surgeon (C.L.) and cardiac imager (J.W.W.) provides an overview of cardiac MRI (CMR) methods relevant to cardiac surgery. Major areas of focus include logistics of performing a CMR exam, as well as established and emerging methods for assessment of cardiac structure, function, valvular performance, and tissue characterization. Regarding tissue characterization, a major area of focus concerns CMR assessment of viability, for which this modality has been shown to provide incremental utility to conventional techniques for detection of presence and transmural extent of infarction, as well as powerful predictive utility of recovery of left ventricular systolic function as well as long term clinical prognosis in patients with an array of clinical conditions, including coronary artery disease and valvular heart disease both before and following cardiac surgery.

Incremental Utility of Right Ventricular Dysfunction in Patients With Myeloproliferative Neoplasm-Associated Pulmonary Hypertension.

BACKGROUND: Myeloproliferative neoplasm (MPN) has been associated with pulmonary hypertension (PH) on the basis of small observational studies, but the mechanism and clinical significance of PH in MPN are not well established. The aims of this study were to expand understanding of PH in a well-characterized MPN cohort via study of PH-related symptoms, mortality risk, and cardiac remodeling sequalae of PH using quantitative echocardiographic methods. METHODS: The population comprised a retrospective cohort of patients with MPN who underwent transthoracic echocardiography: Doppler-derived pulmonary arterial systolic pressure applied established cutoffs for PH (≥35 mm Hg) and advanced PH (≥50 mm Hg); right ventricular (RV) performance was assessed via conventional indices (tricuspid annular plane systolic excursion [TAPSE], S') and global longitudinal strain. Symptoms and mortality were discerned via standardized review. RESULTS: Three hundred one patients were studied; 56% had echocardiography-demonstrated PH (20% advanced) paralleling a high prevalence (67%) among patients with invasively quantified PASP. PH was associated with adverse left ventricular (LV) remodeling indices, including increased myocardial mass and diastolic dysfunction (P ≤ .001 for all): LV mass and filling pressure (P < .01) were associated with PH independent of LV ejection fraction. RV dysfunction by strain and TAPSE and S' increased in relation to PH (P ≤ .001) and was about threefold greater among patients with advanced PH compared with those without PH. Patients with RV dysfunction were more likely to report dyspnea, as were those with advanced PH (P < .05). During median follow-up of 2.2 years, all-cause mortality was 27%. PH grade (hazard ratio, 1.9; 95% CI, 1.1-3.0; P = .012) and TAPSE- and S'-demonstrated RV dysfunction (hazard ratio, 3.3; 95% CI, 1.3-8.2; P = .01) were independently associated with mortality; substitution of global longitudinal strain for TAPSE and S' yielded similar associations of RV dysfunction with death (hazard ratio, 3.2; 95% CI, 1.5-6.7; P = .003) independent of PH. CONCLUSIONS: PH is highly prevalent in patients with MPN and is linked to LV diastolic dysfunction; echocardiography-quantified RV dysfunction augments risk for mortality independent of PH.

Echocardiographic predictors of intraoperative right ventricular dysfunction: a 2D and speckle tracking echocardiography study.

BACKGROUND: Intraoperative or post procedure right ventricular (RV) dysfunction confers a poor prognosis in the post-operative period. Conventional predictors for RV function are limited due the effect of cardiac surgery on traditional RV indices; novel echocardiographic techniques hold the promise to improve RV functional stratification. METHODS: Comprehensive echocardiographic data were collected prospectively during elective cardiac surgery. Tricuspid annular plane systolic excursion (TAPSE), peak RV systolic velocity (S'), and RV fractional area change (FAC) were quantified on transesophageal echo (TEE). RV global and regional (septal and free wall) longitudinal strain was quantified using speckle-tracking echo in RV-focused views. Two intraoperative time points were used for comparison: pre-sternotomy (baseline) and after chest closure. RESULTS: The population was comprised of 53 patients undergoing cardiac surgery [15.1% coronary artery bypass graft (CABG) only, 28.3% valve only, 50.9% combination (e.g. valve/CABG, valve/aortic graft) surgeries], among whom 38% had impaired RV function at baseline defined as RV FAC < 35%. All conventional RV functional indices including TAPSE, S' and FAC declined immediately following CPB (1.5 ± 0.3 vs.1.1 ± 0.3 cm, 8.0 ± 2.1 vs. 6.2 ± 2.5 cm/s, 36.8 ± 9.3 vs. 29.3 ± 10.6%; p < 0.001 for all). However, left ventricular (LV) and RV hemodynamic parameters remained unchanged (LV ejection fraction (EF): 56.8 ± 13.0 vs. 55.8 ± 12.9%; p = 0.40, pulmonary artery systolic pressure (PASP): 26.5 ± 7.4 vs 27.3 ± 6.7 mmHg; p = 0.13). Speckle tracking echocardiographic data demonstrated a significant decline in RV global longitudinal strain (GLS) [19.0 ± 6.5 vs. 13.5 ± 6.9%, p < 0.001]. Pre-procedure FAC, GLS and free wall strain predicted RV dysfunction at chest closure (34.7 ± 9.1 vs. 41.6 ± 8.1%, p = 0.01, 17.7 ± 6.5 vs. 21.8 ± 5.4%; p = 0.03, 20.3 ± 6.4 vs. 24.2 ± 5.8%; p = 0.04), whereas traditional linear RV indices such as TAPSE and RV S' at baseline had no impact on intraoperative RV dysfunction (p = NS for both). CONCLUSIONS: Global and regional RV function, as measured by 2D indices and strain, acutely decline intraoperatively. Impaired RV strain is associated with intraoperative RV functional decline and provides incremental value to traditional RV indices in predicting those who will develop RV dysfunction.