Dobutamine Stress Magnetic Resonance Imaging Research Articles

Left ventricular contractile reserve as a determinant of adverse clinical outcomes: a systematic review.

An abnormal left ventricular contractile reserve is often seen in patients undergoing stress echocardiogram and may indicate the presence of obstructive coronary artery disease. The techniques and indexes used to identify abnormal left ventricular contractile response and its prognostic value in the absence of known causes has not been well studied. To describe the characteristics and clinical outcomes associated with an abnormal left ventricular contractile response, we performed a systematic review that identified 27 eligible studies. A diverse range of indices were utilised to measure left ventricular contractile reserve, most commonly Δleft ventricular ejection fraction in 11 studies. Dobutamine stress echocardiogram was the most commonly performed modality (19 studies) followed by exercise stress echocardiogram (4 studies), dipyridamole stress echocardiogram (2 studies), invasive hemodynamic measurement (1 study) and dobutamine stress magnetic resonance imaging (1 study). All but one study demonstrated a significant association between the absence of left ventricular contractile reserve and increased rate of cardiovascular events, cardiac death and all-cause mortality.

Dobutamine stress MRI in pulmonary hypertension: relationships between stress pulmonary artery relative area change, RV performance, and 10-year survival.

In pulmonary hypertension (PH), right ventricular (RV) performance determines survival. Pulmonary artery (PA) stiffening is an important biomechanical event in PH and also predicts survival based on the PA relative area change (RAC) measured at rest using magnetic resonance imaging (MRI). In this exploratory study, we sought to generate novel hypotheses regarding the influence of stress RAC on PH prognosis and the interaction between PA stiffening, RV performance and survival. Fifteen PH patients underwent dobutamine stress-MRI (ds-MRI) and right heart catheterization. RACREST, RACSTRESS, and ΔRAC (RAC STRESS – RAC REST) were correlated against resting invasive hemodynamics and ds-MRI data regarding RV performance and RV-PA coupling efficiency (n’vv [RV stroke volume/RV end-systolic volume]). The impact of RAC, RV data, and n’vv on ten-year survival were determined using Kaplan–Meier analysis. PH patients with a low ΔRAC (<−2.6%) had a worse long-term survival (log-rank P = 0.045, HR for death = 4.46 [95% CI = 1.08–24.5]) than those with ΔRAC ≥ −2.6%. Given the small sample, these data should be interpreted with caution; however, low ΔRAC was associated with an increase in stress diastolic PA area indicating proximal PA stiffening. Associations of borderline significance were observed between low RACSTRESS and low n’vvSTRESS, Δη’VV, and ΔRVEF. Further studies are required to validate the potential prognostic impact of ΔRAC and the biomechanics potentially connecting low ΔRAC to shorter survival. Such studies may facilitate development of novel PH therapies targeted to the proximal PA.

High-dose dobutamine stress steady-state free precession (SSFP) cine MRI at 3T with patient adaptive local radiofrequency (RF) shimming using dual-source RF transmission.

To prospectively assess the feasibility, image quality, and diagnostic accuracy of high-dose dobutamine stress magnetic resonance imaging (DSMR) using steady-state free precession (SSFP) cine imaging at 3T applying a dual-source radiofrequency (RF) excitation magnetic resonance imaging (MRI) system with parallel transmission and patient adaptive local RF shimming. DSMR using SSFP cine imaging was performed in 44 patients at 3T scheduled for a clinically indicated coronary angiography. The effect of conventional versus dual-source RF transmission was assessed regarding homogeneity of the B1 field, contrast-to-noise ratios (CNRs) at rest, image quality, and diagnostic accuracy of DSMR using long and short axis. The mean percentage of the intended flip angle within the heart increased from 88 ± 9.1% with single-source to 103 ± 5.6% (P < 0.001) dual-source RF transmission. CNR increased for dual-source particularly at the apex (63.4 ± 24.2 vs. 36.5 ± 16.5, P < 0.001) but also at the base of the left ventricle (LV) (50.1 ± 14.8 vs. 39.3 ± 15.8, P < 0.001). Image quality of dual-source was higher both at rest (2.8 ± 0.5 vs. 2.6 ± 0.7, P < 0.001) and stress (2.5 ± 0.7 vs. 2.0 ± 1.0, P < 0.001). The number of segments with severe artifacts or nondiagnostic image quality at stress was lower with dual-source RF transmission (8% vs. 27%, P < 0.001). The diagnostic accuracy of DSMR in coronary territories using dual-source RF transmission was significantly higher (77% vs. 65%, P = 0.04). Patient adaptive local RF shimming using dual-source RF transmission provided significantly improved image quality and higher diagnostic accuracy of SSFP during DSMR at 3T compared to conventional RF transmission.

Myocardial Perfusion, Scarring, and Function in Anomalous Left Coronary Artery From the Pulmonary Artery Syndrome: A Long-Term Analysis Using Magnetic Resonance Imaging

Anomalous left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital heart defect. We aimed to examine the role of cardiac magnetic resonance imaging (MRI) in the long-term surveillance ofrepaired ALCAPA with regard to myocardial scarring, wall motion abnormalities, perfusion deficits, and myocardial function. Twenty-one patients after direct reimplantation of ALCAPA (median age at operation, 2.8 years) wereexamined after a median 10.6 years by MRI at restandunder dobutamine stress conditions, echocardiography, and ergometry. Results were compared with preoperative, immediately postoperative (5 days), and intermediate-term (5.8 years) echocardiography. No early or late deaths occurred. Improvements in indexed left ventricular end-diastolic dimension, ejection fraction, and mitral valve function were observed in all patients. However, MRI at rest showed wall motion abnormalities in 67% and perfusion deficits in 28%. Myocardial scars were seen in 67%. Dobutamine stress MRI detected wall motion abnormalities in 19% and perfusion deficits in 14%, which were not seen on MRI at rest. Exercise testing did not reflect cardiac dysfunction. Although long-term follow-up showed global left ventricular function had improved after ALCAPA repair, MRI showed left ventricular wall motion abnormalities, perfusion deficits, and myocardial scarring were seen in many patients. Dobutamine stress MRI identified deficits that were not evident on MRI at rest, and can therefore be considered a valuable surveillance tool. These results suggest the need for lifelong surveillance of repaired ALCAPA.

Impaired cardiac reserve in asymptomatic patients with moderate pulmonary restenosis late after relief of severe pulmonary stenosis: Evidence for diastolic dysfunction

BackgroundPatients with moderate pulmonary valve restenosis late after relief of severe pulmonary stenosis (PS) may show decreased exercise tolerance. To elucidate the mechanism of decreased exercise tolerance, we evaluated cardiac response to physical and pharmacological stress in these patients and compared results with those of patients with native moderate PS. MethodsTwenty asymptomatic patients with moderate PS were divided into 2 groups: Group I (late after relief of severe PS, n=9), and Group II (no previous intervention, n=11). All patients underwent an exercise test, dobutamine stress (DS) MRI, and delayed contrast enhanced MRI. The response to physical and pharmacological stress was compared between both groups. ResultsGroup I showed impaired exercise capacity compared to Group II (VO2max=72.8%±3.5% vs. 102.5%±16.3%, p<0.001). During DS-MRI, RV-SV increased in Group II, but not in Group I (+13±8ml, −5±8ml, p<0.001). RV end‐diastolic volume decreased significantly in Group I patients (p=0.006) while it did not significantly change in Group II patients. The amount of RV-SV increase (∆ RV-SV) correlated negatively with the period of moderate PS existence and the current PG in Group I (r=−0.82, p=0.007, and r=−0.68, p=0.04, respectively) but not in Group II (r=0.45, p=0.1, and r=0.40, p=0.2, respectively). Furthermore, ∆ RV-SV correlated negatively with the PG before valvuloplasty (r=−0.76, p=0.02). ConclusionImpaired exercise capacity in patients with moderate pulmonary restenosis after relief of severe PS is probably caused by inability to increase RV-SV. Disturbed RV filling properties, worsening in time, might play a role.

Update on Dobutamine Stress Magnetic Resonance

Over the past years dobutamine stress magnetic resonance imaging (DSMR) has matured into a highly valuable clinical tool for the assessment of myocardial ischemia and viability. Furthermore, the results of DSMR can be utilized to direct clinical management and to determine cardiac prognosis. This article gives an update on recently published data regarding the performance of DSMR including technical developments, diagnostic accuracy, prognosis, and the implications on clinical management in patients with coronary artery disease (CAD).

High-dose dobutamine stress SSFP cine MRI at 3 Tesla with patient adaptive local RF shimming using dual-source RF transmission

Background Image quality of cine imaging using steady state free precession (SSFP) sequences at 3T is insufficient due to increased RF-inhomogeneity (B1 field) and the high sensitivity of SSFP sequences to off-resonance artefacts. Recently, the introduction of a dual source RF transmission system with patient-adaptive local RF-shimming has led to a significant improvement of image quality of SSFP imaging at 3T. The objective of this study was to prospectively evaluate the feasibility, image quality and diagnostic accuracy of high-dose dobutamine stress magnetic resonance imaging (DSMR) at 3T comparing dual-source versus single-source transmit technology.

Assessment of warranty time for dobutamine stress magnetic resonance imaging in 3138 consecutive patients: a bi-center study

Summary We aimed to determine the prognostic value of wall motion assessment during high-dose dobutamine stress cardiac magnetic resonance imaging (DCMR) for the prediction of hard cardiac events in a large patient cohort and within a long follow-up duration. DCMR can accurately identify between patients with inducible ischemia who are at increased risk for future hard cardiac events and revascularization procedures. Within the ‘primary warranty time’ of 3 years after DCMR excellent outcomes (annual hard cardiac event rate 90 days after the MR-scans were prospectively collected at least 6 months after DCMR. Results

Effect of age on exercise capacity and cardiac reserve in patients with pulmonary atresia with intact ventricular septum after biventricular repair

OBJECTIVESIn patients with pulmonary atresia with intact ventricular septum (PAIVS), biventricular repair is considered to be the optimal treatment option in the absence of significant right ventricular (RV) hypoplasia. However, long-term clinical outcome studies are limited. We evaluated exercise capacity and cardiac function during pharmacological stress in children and young adults with PAIVS after biventricular repair.METHODSTen PAIVS patients after biventricular repair, with a median age of 12 years (range 9-42 years), underwent a cardiopulmonary exercise test, dobutamine stress magnetic resonance imaging (DS-MRI) and delayed contrast enhancement (DCE) MRI.RESULTSThe patients' ages negatively correlated with exercise capacity (r = -0.72, P = 0.01) as well as left (LV) and RV stroke volume (SV) response to pharmacological stress (r = -0.72, P = 0.02; and r = -0.64, P = 0.04; respectively), Furthermore, older age was associated with decreased RV E/A volume ratio and increased pulmonary late diastolic forward flow percentage (r = 0-0.65, P = 0.04, r = 0.66, P = 0.03, respectively). RV E/A volume ratio positively correlated with RV-SV response to DS-MRI (r = 0.77, P = 0.009). and O(2)-pulse during physical stress correlated with biventricular SV response to DS-MRI. No RV or LV ventricular myocardial fibrosis was detected.CONCLUSIONSIn PAIVS patients after biventricular repair exercise capacity and cardiac reserve decrease with age. These findings appear to be related to impaired diastolic RV function and decreased RV filling, indicating that the function of the relatively small RV deteriorates with time

Cardiac magnetic resonance myocardial feature tracking correlates with natural radial strain and corresponds to inotropic stimulation

Summary We have demonstrated that cardiac magnetic resonance (CMR) myocardial feature tracking (FT) and natural radial strain correlate and correspond to inotropic stimulation. CMR-FT has the potential for quantitative wall motion assessment at rest and during dobutamine stress magnetic resonance (DSMR) imaging. Background CMR-FT is a recently introduced technique for tissue voxel motion tracking on standard steady-state free precession (SSFP) images to derive radial myocardial mechanics. CMR-FT has the potential to facilitate DSMR analysis however has not yet been compared to external reference standards (with stress) such as SSFP derived natural radial strain. Methods 10 healthy subjects were studied at 1.5 Tesla. LV shortaxis radial strain ErrSAX was derived from SSFP cine images using dedicated CMR-FT software (Diogenes MRI prototype, Tomtec, Germany) at rest and during dobutamine stress (10 and 20 μg * kg-1* min-1). Natural radial strain values (loge [End-systolic wall thickness/ end-diastolic wall thickness]) were calculated in identical segments as analysed for ErrSAX using commercially available software (Philips View Forum, The Netherlands). 95% confidence intervals (CI) of the difference and p-values were calculated to compare the 2 techniques. Results In all volunteers strain parameters could be derived from the SSFP images at rest and stress. ErrSAX values showed significantly increased contraction with DSMR (rest: 19.6±14.6; 10 μg: 31.8±20.9; 20 μg: 42.4±25.5, p<0.05). Natural radial strain values increased with dobutamine (rest: 24±8.9; 10 μg: 36.5±8.9; 20 μg: 44.2 ±8.5, p<0.05). There was reasonable agreement between mean ErrSAX and natural radial strain at rest and with dobutamine stress (figure 1 and table 1) as determined by 95% CI of the difference. Conclusions

Decreased exercise capacity in ‘asymptomatic’ patients late after relief of severe pulmonary stenosis and moderate restenosis: evidence for diastolic dysfunction

Summary We concluded that close and regular follow up of asymptomatic patients with a history of previous intervention for PS and residual moderate PS by stress testing is recommended. This might reveal cardiac functional deterioration, which could be an indicator for the earlier intervention in this group of patients to avoid permanent cardiac dysfunction. Background Little is known about the management of moderate pulmonary restenosis after relief for severe pulmonary valve stenosis (PS).We evaluated cardiac response to physical and pharmacological stress late after relief of severe PS in these patients. Methods Twenty asymptomatic patients with moderate PS were divided into 2 groups: Group I (late after relief of severe PS, n = 9), and Group II (no previous intervention, n = 11). All patients underwent an exercise test, dobutamine stress (DS) MRI, and delayed contrast enhanced MRI. The response to physical and pharmacological stress was compared between both groups. Results Group I showed impaired exercise capacity compared to Group II (VO2max = 72.8 ± 3.5 vs. 103 ± 16%, p = 0.01). At rest, both groups showed normal systolic function. Majority of Group I patients have impaired RV diastolic function (82% vs. 33%, P = 0.004). During DSMRI, right ventricular stroke volume (RV-SV) increased in Group II but not in Group I (+13 ± 8 ml, - 5 ± 8 ml, p < 0.001). In Group I, RV peak flow rate ratio correlated positively with Δ RV-SV (r = 0.58, p = 0.01), and negatively with the period of moderate PS existence (r = -0.77, p = 0.01- Figure 1). VO2max and O2-pulse were correlated with RV-SV response to DS-MRI. Conclusions

Effect of age on exercise capacity and cardiac reserve in patients with pulmonary atresia with intact ventricular septum after biventricular repair

In patients with pulmonary atresia with intact ventricular septum (PAIVS), biventricular repair is considered to be the optimal treatment option in the absence of significant right ventricular (RV) hypoplasia. However, long-term clinical outcome studies are limited. We evaluated exercise capacity and cardiac function during pharmacological stress in children and young adults with PAIVS after biventricular repair. Ten PAIVS patients after biventricular repair, with a median age of 12 years (range 9-42 years), underwent a cardiopulmonary exercise test, dobutamine stress magnetic resonance imaging (DS-MRI) and delayed contrast enhancement (DCE) MRI. The patients' ages negatively correlated with exercise capacity (r=-0.72, P=0.01) as well as left (LV) and RV stroke volume (SV) response to pharmacological stress (r=-0.72, P=0.02; and r=-0.64, P=0.04; respectively), Furthermore, older age was associated with decreased RV E/A volume ratio and increased pulmonary late diastolic forward flow percentage (r=0-0.65, P=0.04, r=0.66, P=0.03, respectively). RV E/A volume ratio positively correlated with RV-SV response to DS-MRI (r=0.77, P=0.009). and O2-pulse during physical stress correlated with biventricular SV response to DS-MRI. No RV or LV ventricular myocardial fibrosis was detected. In PAIVS patients after biventricular repair exercise capacity and cardiac reserve decrease with age. These findings appear to be related to impaired diastolic RV function and decreased RV filling, indicating that the function of the relatively small RV deteriorates with time.

Dobutamine stress MRI in repaired tetralogy of Fallot with chronic pulmonary regurgitation: A comparison with healthy volunteers

BackgroundTo compare the ventricular response to dobutamine stress between adult patients with chronic pulmonary regurgitation (PR) after repair of tetralogy of Fallot (r-TOF) and healthy volunteers using a staged dobutamine stress MR (DS-MR) protocol. MethodsEighteen r-TOF patients (median age 31.9years, range 16.2–60.1) with severe PR and 10 healthy controls (median age 40.6years, range 23.9–51.8) completed staged DS-MR (baseline, 10 and 20μg/kg/min) with ventricular volumetry and pulmonary flow quantification. Comparative analysis involved 3-way ANOVA, t-test, regression analysis, and coefficient of variance. ResultsAll controls had significant increase of ejection fraction (EF) at each stress level for both ventricles (normal contractile reserve, all p<0.05). In r-TOF patients (RV-EDV 126±27ml/m2, RV-EF 55±7%, LV-EF 58±6%, PR-fraction 43±15%), low-dose DS-MR at 10μg/kg/min demonstrated normal biventricular contractile reserve as seen in volunteers. On increase from 10 to 20μg/kg/min a subgroup showed worsening ejection fraction (n=8, p<0.05), mainly due to lack of reduction or even increase of RV-ESV, while the remainder responded with further reduction of RV-ESV and RV-EDV (n=10, p<0.05) and a non-significant trend to increased EF. This different response could not be predicted at baseline. ConclusionsIn r-TOF patients with chronic PR, DS-MR at 10μg/kg/min showed normal biventricular systolic response compared with controls. Increase to 20μg/kg/min provoked abnormal RV-ESV response in some r-TOF patients, suggesting presence of ventricular systolic dysfunction not evident at rest.

Cardiovascular magnetic resonance myocardial feature tracking for quantitative viability assessment in ischemic cardiomyopathy

BackgroundLow dose dobutamine stress magnetic resonance imaging is valuable to assess viability in patients with ischemic cardiomyopathy. Analysis is usually qualitative with considerable operator dependency. The aim of the current study was to investigate the feasibility of cine images derived quantitative cardiac magnetic resonance (CMR) myocardial feature tracking (FT) strain parameters to assess viability in patients with ischemic cardiomyopathy. Methods15 consecutive patients with ischemic cardiomyopathy referred for viability assessment were studied at 3T at rest and during low dose dobutamine stress (5 and 10μg/kg/min of dobutamine). Subendocardial and subepicardial circumferential (Eccendo and Eccepi) and radial (Err) strains were assessed using steady state free precession (SSFP) cine images orientated in 3 short axis slices covering 16 myocardial segments. ResultsDysfunctional segments without scar (n=75) improved in all three strain parameters: Eccendo (Rest: −10.5±6.9; 5μg: −12.1±6.9; 10μg: −14.1±9.2; p<0.05), Eccepi (Rest: −7±4.8; 5μg: −8.2±5.5; 10μg: −9.1±5.9; p<0.05) and Err (Rest: 11.7±8.3; 5μg: 16±10.9; 10μg: 16.5±12.8; p<0.05).There was no response to dobutamine in dysfunctional segments with scar transmurality above 75% (n=6): Eccendo (Rest: −4.7±3.0; 5μg: −2.9±2.5; 10μg: −6.6±3.3; p=ns), Eccepi (Rest: −2.9±2.9; 5μg: −5.4±3.9; 10μg: −4.5±4.2; p=ns) and Err (Rest:9.5±5; 5μg:5.4±6.2; 10μg:4.9±3.3; p=ns). Circumferential strain (Eccendo, Eccepi) improved in all segments up to a transmurality of 75% (n=60; p<0.05). Err improved in segments <50% transmurality (n=45; p<0.05) and remained unchanged above 50% transmurality (n=21; p=ns). ConclusionsCMR-FT is a novel technique, which detects quantitative wall motion derived from SSFP cine imaging at rest and with low dose dobutamine stress. CMR-FT holds promise of quantitative assessment of viability in patients with ischemic cardiomyopathy.

Exercise capacity and cardiac reserve in children and adolescents with corrected pulmonary atresia with intact ventricular septum after univentricular palliation and biventricular repair

Management of pulmonary atresia with intact ventricular septum is challenging and depends on the severity of right ventricular hypoplasia. Clinical outcomes of biventricular repair seem favorable to univentricular palliation, but data on superiority of biventricular repair regarding exercise capacity are conflicting. We investigated the response to physical and pharmacologic stress in patients with surgically corrected pulmonary atresia with intact ventricular septum. Sixteen patients (7 patients after univentricular palliation, age 11.8 ± 2.6 years; 7 patients after biventricular repair, age 12.9 ± 2.7 years; and 2 patients after 1.5 ventricular repair, age 12 and 19 years) underwent cardiopulmonary exercise test, dobutamine stress magnetic resonance imaging, and delayed contrast-enhanced magnetic resonance imaging. The univentricular group showed impaired exercise capacity in contrast with normal exercise capacity in the biventricular group. Left ventricular ejection fraction increased in both groups. With dobutamine, left ventricular stroke volume increased only in the biventricular group (+11.3 ± 5.0 mL, P<.001) and not in the univentricular group (-0.04 ± 3.6 mL, P=.9). Heart rate increase was inadequate in the univentricular group. Maximum oxygen consumption and oxygen pulse were strongly correlated with left ventricular stroke volume during stress but not at rest. The results of the 2 patients after 1.5 ventricular repair were comparable to those of the univentricular group. No myocardial fibrosis was detected. Impaired exercise capacity in children and adolescents with pulmonary atresia with intact ventricular septum after univentricular palliation is related to decreased cardiac reserve and inadequate chronotropic response. Young patients with pulmonary atresia with intact ventricular septum after biventricular repair show normal exercise capacity and cardiac reserve.

Nichtinvasive Diagnostik der chronisch stabilen koronaren Herzkrankheit: evidenzbasierte und nicht evidenzbasierte diagnostische Algorithmen

In Germany, every second left heart catheterization has no immediate interventional or surgical consequence. One main reason for this limited quality of indication of many left heart catheterizations is presumably the inaccuracy of preinvasive testing that is mainly based on clinical evaluation and exercise ECG in Germany. However, exercise electrocardiography has several limitations. The central issues are the inability to exercise in many, especially elderly patients, and the missing interpretability of the stress ECG in cases with already pathological rest ECG. In 2006, the "Nationale Versorgungsleitlinie Chronische KHK (NVL KHK)" was published in Germany, adopting for the first time the evidence-based algorithms of the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for non-invasive stress testing and complementary stress imaging. Stress imaging methods considered comparable and interchangeable are the following: stress echocardiography combined with physical or pharmacological stress testing, myocardial perfusion imaging with physical or pharmacological stress testing, dobutamine stress magnetic resonance imaging (DSMR), or myocardial perfusion magnetic resonance imaging (MRI). Basically, no stress imaging method is definitely superior to the others, each method has its own advantages and disadvantages that should be considered and adjusted to the individual patient. Of pivotal importance of all stress imaging methods is the high negative predictive value of 99% of a normal study predicting a very low (< 1%) cumulative likelihood of cardiac death or myocardial infarction for at least the next 12 months. Hence, in most clinical circumstances, coronary angiography is not necessary during the 12 months subsequent to a normal stress imaging study. In contrast to these established and evidence-based recommendations of the "Nationale Versorgungsleitlinie Chronische KHK" mainly focusing on ischemia stress imaging, many diagnostic centers have developed their own non-evidence based algorithms. In these non-evidence based algorithms the morphology-oriented non-invasive CT coronary angiography has taken over the diagnostic part of evidence-based ischemia stress imaging. However, beyond the scientifically established prognostic value of calcium scoring, there is so far no scientific evidence showing that morphology-oriented CT coronary angiography protocols are superior to functional stress imaging. A new innovative approach of staged non-invasive diagnostics for patients with intermediate likelihood (10-90%) of coronary artery disease are the 2010 recommendations of the National Institute for Health and Clinical Excellence (NICE) guiding the National Health Service (NHS) in the United Kingdom. Following this guidance, in patients with an estimated likelihood of CAD of 10-29% CT calcium scoring should be offered as first-line method, in patients with an estimated likelihood of CAD of 30-60% non-invasive functional imaging should be offered primarily, and in patients with an estimated likelihood of CAD of 61-90%, as in patients with an estimated likelihood of CAD of more than 90%, invasive coronary angiography should be preferred.

Cardiac allograft vasculopathy: current knowledge and future direction

Cardiac allograft vasculopathy (CAV) is a unique form of coronary artery disease affecting heart transplant recipients. Although prognosis of heart transplant recipients has improved over time, CAV remains a significant cause of mortality beyond the first year of cardiac transplantation. Many traditional and non-traditional risk factors for the development of CAV have been described. Traditional risk factors include dyslipidemia, diabetes and hypertension. Non-traditional risk factors include cytomegalovirus infection, HLA mismatch, antibody-mediated rejection, and mode of donor brain death. There is a complex interplay between immunological and non-immunological factors ultimately leading to endothelial injury and exaggerated repair response. Pathologically, CAV manifests as fibroelastic proliferation of intima and luminal stenosis. Early diagnosis is paramount as heart transplant recipients are frequently asymptomatic owing to cardiac denervation related to the transplant surgery. Intravascular ultrasound (IVUS) offers many advantages over conventional angiography and is an excellent predictor of prognosis in heart transplant recipients. Many non-invasive diagnostic tests including dobutamine stress echocardiography, CT angiography, and MRI are available; though, none has replaced angiography. This review discusses the risk factors, pathogenesis, and diagnosis of CAV and highlights some current concepts and recent developments in this field.

Wall motion recovery in dobutamine stress magnetic resonance imaging

Methods DSMR was performed in twenty-eight consecutive patients with suspected or known CAD scheduled for clinically indicated invasive coronary angiography. Each patient underwent routine DSMR including cine imaging at rest and during dobutamine infusion. Additionally, three standard short axis and longitudinal axis views were obtained after five, ten and fifteen minutes during the recovery period in order to detect persisting wall motion abnormalities in ischemic myocardial territories, which were assigned to coronary arteries based on the 17 segment model. Intermediate and severe coronary stenosis were defined as 50-75% and >75% luminal narrowing using invasive coronary angiography, respectively (figure 1). All patients received esmolol after stopping the dobutamine infusion to achieve a heart rate under 100bpm.

Myocardial feature tracking for viability assessment in ischemic cardiomyopathy

Background Low dose dobutamine stress magnetic resonance imaging (LDDSMR) is a widely accepted technique for assessment of hibernating myocardium in patients with ischemic cardiomyopathy (ICMP). It is particularly helpful in patients with intermediate transmurality of scar where prediction of functional recovery by late gadolinium enhancement imaging (LGE) alone is difficult. Analysis of LDDSMR is usually based on visual assessment and is therefore considerably operator dependant. Recently myocardial feature tracking (FT) has been introduced. It tracks tissue voxel motion of cine-MR images to assess circumferential and radial myocardial strain independent of additional sequences.

Dobutamine stress MRI catheterisation in patients with hypoplastic left heart syndrome after Fontan completion: preliminary results

Exercise tolerance is often impaired in children with hypoplastic left heart syndrome(HLHS). It has been hypothesised this may be related to diastolic dysfunction of the single systemic right ventricle (RV), ventricular hypertrophy or to restricted pre-load from limited pulmonary venous return in Fontan physiology.