Cost-Minimization analysis for cardiac revascularization in 12 healthcare systems based on the EuroCMR/SPINS registries

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): EuroCMR registry (Life Sciences GE Healthcare, Medtronic Inc., Minneapolis MN, USA; Novartis International AG, Basel, Switzerland; Siemens Healthcare, Erlangen, Germany), SPINS registry (Siemens Healthineers, Erlangen, Germany; Bayer AG, Leverkusen, Germany)

Background

Coronary artery disease (CAD) is a major contributor to the public health burden. Stress perfusion cardiac magnetic resonance (CMR) has an excellent accuracy to detect CAD, but data on its cost effectiveness are scarce.

Purpose

To compare the costs of a CMR-guided strategy vs 2 invasive strategies based on 2 large international CMR registries.

Methods

In the EuroCMR registry (n = 3’647, 59 centers, 18 countries) and the US-based SPINS registry (n = 2’349, 13 centers, 11 states) costs were calculated for 12 healthcare systems (8 Europe, US, 2 Latin America, 1 Asia). They included diagnostic examinations (CMR, X-ray coronarography (CXA) with/without FFR), revascularizations, and complications during a 1-year follow-up. Endpoints in both registries were all-cause and cardiovascular (CV) death, sudden cardiac death (SCD), aborted SCD, non-fatal myocardial infarction (nf-MI), and stroke. 7 sub-group analyses covered low to high-risk cohorts. Patients with ischemia-positive CMR underwent CXA and revascularization (percuteneous and surgical intervention) at the treating physician’s discretion (=CMR + CXA-strategy). In the hypothetical invasive CXA + FFR-strategy, costs were calculated for an initial CXA and an FFR in vessels with ≥50% stenoses assuming the same proportion of revascularizations/complications as in the CMR + CXA-strategy and FFR positive rates as given in the literature. In the CXA-only strategy, costs included CXA and revascularizations of ≥50% stenoses.

Results

Revascularizations were performed in 8.0% and 6.2% (p < 0.01) of SPINS and EuroCMR patients, respectively. Consistent cost savings were observed for the CMR + CXA strategy vs CXA + FFR in all 12 healthcare systems ranging from 42 ± 20% and 52 ± 15% in the low-risk EuroCMR and SPINS patients with atypical chest pain (CV-death and nf-MI 0.4-0.7%/y), respectively, to 31 ± 16% in the high-risk SPINS patients (CV-death and nf-MI 3.2%/y) with known CAD (p < 0.0001 vs 0 in all groups, Fig 1/2). Cost savings were even higher vs CXA-only with 63 ± 11%, 73 ± 6%, and 52 ± 9%, respectively (p < 0.0001 vs 0 in all groups, Fig 2).

Conclusions

In 12 healthcare systems, a CMR + CXA-strategy yielded consistent moderate to high cost savings compared to a hypothetical CXA + FFR-strategy over the entire spectrum of risk. Cost savings were consistently high vs a CXA-only strategy for all risk groups.

Figure 1: SPINS refers to the subgroup of patients with suspected CAD (n = 1’530), EuroCMR (= suspected CAD; n = 3’647). EuroCMR vs SPINS ns. Countries per region are listed in alphabetical order.

Figure 2: Top: CMR + CXA vs CXA + FFR: ANOVA: overall p = 0.0017, * vs EuroCMR typ angina: p < 0.005 (Scheffe post-hoc testing). Bottom: CMR + CXA vs CXA-only: ANOVA overall p < 0.0001, * vs SPINS with CAD and vs EuroCMR typ A: p < 0.0001; † vs SPINS with CAD: p < 0.03; ‡ vs EuroCMR typ A: p < 0.0001; § vs SPINS with CAD: p < 0.002; ║ vs EuroCMR typ: p < 0.002 (Scheffe post-hoc tesing)

Association of QRS-T angle and Late Gadolinium Enhancement in patients with a Clinical Suspicion of Myocarditis

Objective: To investigate the association of a wide QRS-T angle on the surface ECG and late gadolinium enhancement on contrast-enhanced cardiovascular magnetic (CMR) imaging in patients with clinically suspected myocarditis. Background: Diagnosis and risk stratification in patients with suspected myocarditis is particularly challenging due to a great spectrum of clinical presentations. Late gadolinium enhancement (LGE) visualizes myocardial necrosis and fibrosis in patients with biopsy-proven myocarditis. The presence or absence of late gadolinium enhancements in these patients is prognostically meaningful. The QRS-T angle from the surface ECG, on the other hand, may serve as a simple and easily available risk marker in suspected myocarditis. Methods: We enrolled 97 consecutive patients that were referred to CMR imaging for a clinical suspicion of myocarditis. All patients obtained a standardized digital 12-lead ECG for the calculation of the QRS-T angle and underwent contrast-enhanced CMR imaging. Patients were divided into two groups according to the absence or presence of LGE on CMR. Results: 78 of 97 patients with suspected myocarditis had LGE on CMR. Patients with LGE had wider QRS-T angles as compared to the patient group without LGE (53.95-47.5 vs. 26.2-21.2; p<0.001). The sensivity, specificity, negative predictive value and positive predictive value for a QRS-T angle above 90 degrees for LGE positive myocarditis were 16.5%, 100%, 24.7%, and 100%, respectively. Conclusion: A wide QRS-T angle of 90 degrees or more is linked to myocardial fibrosis or necrosis (late gadolinium enhancement) in patients with suspected myocarditis.

QRS-T-angle in Patients with ST-Segment Elevation Myocardial Infarction (STEMI) - a Comparison with Cardiac Magnetic Resonance Imaging

Background: The QRS-T angle from the surface EKG is a promising prognostic marker in patients with coronary artery disease. Cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) offers high resolution imaging of myocardial damage. We investigated the association of the QRS-T angle and the extent of myocardial damage as assessed by LGE in patients with acute ST-segment myocardial infarction (STEMI) Methods: 169 patients with STEMI obtained a standardized digital 12-lead EKG on admission for the calculation of the QRS-T angle and underwent CMR imaging for analysis of infarct size by LGE within the first week. Patients were divided into groups: (1) abnormal QRS-T angle ≥ 90 degree and (2) QRS-T angle < 90 degree. Results: Patients with a QRS-T angle of 90 degree or more had larger infarcts (36.5±12.4 vs. 13.3±9.5; p<0.001) and lower ejection fraction (42.9±12.1% vs. 50.6±10.6%; p<0.001). Conclusion: The extent of myocardial damage as measured by the gold standard LGE is associated with a larger QRS-T angle calculated from the surface EKG.

2015 Update on Acute Adverse Reactions to Gadolinium based Contrast Agents in Cardiovascular MR. Large Multi-National and Multi-Ethnical Population Experience With 37788 Patients From the EuroCMR Registry

OBJECTIVES

Specifically we aim to demonstrate that the results of our earlier safety data hold true in this much larger multi-national and multi-ethnical population.

BACKGROUND

We sought to re-evaluate the frequency, manifestations, and severity of acute adverse reactions associated with administration of several gadolinium- based contrast agents during routine CMR on a European level.

METHODS

Multi-centre, multi-national, and multi-ethnical registry with consecutive enrolment of patients in 57 European centres.

RESULTS

During the current observation 37,788 doses of Gadolinium based contrast agent were administered to 37,788 patients. The mean dose was 24.7 ml (range 5-80 ml), which is equivalent to 0.123 mmol/kg (range 0.01 - 0.3 mmol/kg). Forty-five acute adverse reactions due to contrast administration occurred (0.12%). Most reactions were classified as mild (43 of 45) according to the American College of Radiology definition. The most frequent complaints following contrast administration were rashes and hives (15 of 45), followed by nausea (10 of 45) and flushes (10 of 45). The event rate ranged from 0.05% (linear non-ionic agent gadodiamide) to 0.42% (linear ionic agent gadobenate dimeglumine). Interestingly, we also found different event rates between the three main indications for CMR ranging from 0.05% (risk stratification in suspected CAD) to 0.22% (viability in known CAD).

CONCLUSIONS

The current data indicate that the results of the earlier safety data hold true in this much larger multi-national and multi-ethnical population. Thus, the "off-label" use of Gadolinium based contrast in cardiovascular MR should be regarded as safe concerning the frequency, manifestation and severity of acute events.

Cardiac MRI: T2-Mapping Versus T2-Weighted Dark-Blood TSE Imaging for Myocardial Edema Visualization in Acute Myocardial Infarction

PURPOSE

To assess the diagnostic accuracy of T2 mapping for the detection of myocardial edema in acute myocardial infarction (AMI), and to compare this diagnostic accuracy with that of the current standard for myocardial edema imaging, which is T2w dark-blood TSE imaging.

MATERIALS AND METHODS

29 patients with AMI were examined at 1.5 T. For the visualization of myocardial edema, T2 maps, calculated from three T2w SSFP images, and T2w dark-blood TSE images were acquired in standard short- and long-axis views. Cine SSFP images were acquired for the analysis of left ventricular (LV) function and late gadolinium enhancement images (LGE) for the visualization of myocardial necrosis. The T2 maps as well as the T2w dark-blood TSE images were evaluated twice independently from the cine SSFP and LGE images. The presence or absence of myocardial edema was rated visually for each LV segment. As the standard of reference, the infarct zone was defined based on the cine SSFP and the LGE images.

RESULTS

In this segment-based analysis, T2 mapping showed a sensitivity of 82 % and a specificity of 94 % for the detection of edema in the infarct zone. T2w dark-blood TSE imaging revealed a sensitivity of 50 % and a specificity of 98 %. T2 mapping showed a higher intra-rater agreement compared to T2w dark-blood TSE imaging (κ: 0.87 vs. 0.76).

CONCLUSIONS

T2 mapping allows for the visualization of myocardial edema in AMI with a high sensitivity and specificity, and features better diagnostic accuracy in terms of a higher sensitivity compared to T2w dark-blood TSE imaging. Citation Format: • Naßenstein K, Nensa F, Schlosser T et al. Cardiac MRI: T2-Mapping Versus T2-Weighted Dark-Blood TSE Imaging for Myocardial Edema Visualization in Acute Myocardial Infarction. Fortschr Röntgenstr 2014; 186: 166 - 172.

[Extensive left ventricular myocardial fat deposition detected by cardiac MRI]

Although it is well known from pathological studies that intramyocardial fat deposition frequently occurs after left ventricular myocardial infarction, a left ventricular fat deposition is rarely diagnosed in the clinical routine. We report the case of extensive fat deposition in the left ventricular myocardium which was detected by routine cardiac magnetic resonance imaging.

Cardiac MRI: estimation of changes in normalized myocardial gadolinium accumulation over time after contrast injection in patients with acute myocarditis and healthy volunteers

PURPOSE

An increased normalized gadolinium accumulation (NGA) in the myocardium during early washout has been used for the diagnosis of acute myocarditis (AM). Due to the fact that the pharmacokinetics of contrast agents are complex, time-related changes in NGA after contrast injection are likely. Because knowledge about time-related changes of NGA may improve the diagnostic accuracy of MR, our study aimed to estimate the time course of NGA after contrast injection in patients as well as in healthy volunteers.

MATERIALS AND METHODS

An ECG-triggered inversion recovery SSFP sequence with incrementally increasing inversion times was repetitively acquired over the 15 minutes after injection of 0.2 Gd-DTPA per kg body weight in a 4-chamber view in 15 patients with AM and 20 volunteers. The T 1relaxation times and the longitudinal relaxation rates (R1) of the myocardium and skeletal musculature were calculated for each point in time after contrast injection. The time course of NGA was estimated based on the linear relationship between R1 and tissue Gd concentration.

RESULTS

NGA decreased over time in the form of a negative power function in patients with AM and in healthy controls. NGA in AM tended to be higher than in controls (p > 0.05).

CONCLUSION

NGA rapidly changes after contrast injection, which must be considered when measuring NGA. Although we observed a trend towards higher NGA values in patients with AM with a maximum difference one minute after contrast injection, NGA did not allow us to differentiate patients with AM from healthy volunteers, because the observed differences did not reach a level of significance.

Dobutamine stress cardiovascular magnetic resonance imaging in patients after invasive coronary revascularization with stent placement

BACKGROUND

High-dose dobutamine stress magnetic resonance (DSMR) is a well-established imaging technique for the detection of coronary artery disease (CAD).

PURPOSE

To investigate the value of DSMR for the detection of in-stent restenoses (ISR) in patients with prior coronary stenting, using invasive coronary angiography (ICA) as the standard of reference.

MATERIAL AND METHODS

50 patients with 74 stents and without wall motion abnormalities at rest were examined on a 1.5T MR scanner and underwent ICA for clinical reasons within 14 days after DSMR examination. A dobutamine/atropine stress protocol was employed until age-predicted heart rate was achieved, and imaging was performed in at least three long- and three short-axis views using a segmented steady-state free precession sequence (repetition/echo time [TR/TE] 3/1.5 ms, flip angle 60 degrees). All examinations were read by an experienced cardiologist and radiologist in consensus, with myocardial ischemia being defined as a new stress-induced wall motion abnormality in at least one myocardial segment. Statistical analysis was performed on a per-vessel (left circumflex artery [LCX], left anterior descending artery [LAD], and right coronary artery [RCA]) basis and with regard to the number of affected vessels (one-, two- or three-vessel disease).

RESULTS

ICA yielded seven ISR, of which one was missed by DSMR (sensitivity 86%, 95% confidence interval [CI] 0.42-0.99). Sixty-seven coronary arteries showed no ISR in ICA; however, due to new wall motion abnormalities, seven ISR were suspected in DSMR (2xRCA, 3xLCX, and 2xLAD; sensitivity 86%, specificity 90%, positive predictive value 46%, negative predictive value 98%, and diagnostic accuracy 89%). The per-vessel analysis of the three main coronary arteries revealed highest sensitivity (100%), specificity (93%), and diagnostic accuracy (94%) for the LAD.

CONCLUSION

High-dose DSMR is an accurate, noninvasive technique for the detection of ISR and reliably allows identification of patients who need to undergo control ICA.

Comparison of aortic valve area measured by magnetic resonance imaging and dual-source computed tomography

BACKGROUND

Aortic valve stenosis is the most common type of valve lesion in Europe and North America. Patient treatment is based on disease severity, which is classified by determining the aortic valve area (AVA).

PURPOSE

To compare dual-source computed tomography (DSCT) with magnetic resonance (MR) imaging for quantifying AVA.

MATERIAL AND METHODS

Thirty-two patients, 28 with normal aortic valve function and four with aortic valve stenosis, who underwent DSCT coronary angiography (Somatom Definition; Siemens, Erlangen, Germany), were included in this study. Retrospective ECG-gated contrast-enhanced DSCT scans with dose-reducing tube current modulation were performed, and data sets were reconstructed in 3% steps of the R-R interval (slice thickness 0.75 mm, increment 0.6 mm). Planimetry of the AVA in systole was assessed on cross-sectional images by multiplanar reformations. Within 48 hours, MR was performed with a 1.5T scanner (Magnetom Sonata; Siemens, Erlangen, Germany) using a balanced steady-state free-precession cine sequence (repetition/echo time 3/1.5 ms, flip angle 60 degrees, spatial resolution 1.4 x 1.4 mm(2)). Cine sequences of the left ventricular outflow tract (LVOT) were obtained in two orthogonal planes, and MR planimetry was performed on cross-sectional images of the aortic valve perpendicular to the LVOT images.

RESULTS

AVA assessment by DSCT and MR was feasible in all 32 patients. Mean AVA values determined by DSCT and MR were 4.73+/-1.5 cm(2) and 4.69+/-1.4 cm(2), respectively. A strong positive correlation was found between both imaging modalities (R=0.98, P<0.001). Bland-Altman analysis demonstrated an excellent intermodality agreement, with a slight underestimation of AVA by DSCT. The mean difference was -0.04 cm(2), with a standard deviation of 0.32 cm(2).

CONCLUSION

Retrospective ECG-gated contrast-enhanced DSCT with tube current modulation provides an accurate imaging technique for the assessment of the AVA. Further studies are required to determine whether DSCT also allows for AVA quantification in patients with aortic valve stenosis.

Myocardial scars are an underestimated cardiovascular burden in patients with internal carotid artery stenosis

BACKGROUND

Patients with internal carotid artery (ICA) stenosis have an increased incidence of coronary heart disease. Evidence about the incidence of clinically silent myocardial infarction (MI) in these patients is limited. Contrast-enhanced cardiac magnetic resonance (CMR) imaging allows for the detection of minor myocardial damage.

OBJECTIVE

We tested whether patients with ICA stenosis exhibit a relevant incidence of silent MI when assessed by CMR.

METHODS

In a single-center study, 77 consecutive patients (age 68 +/- 7 years) with suspected ICA stenosis were imaged prospectively with a combined MRI protocol including T(1), T(2), diffusion-weighted imaging, fluid-attenuated inversion recovery, and contrast-enhanced MR angiography (CEMRA) imaging of the brain and a short (11 min) CMR protocol with left ventricular function and late gadolinium enhancement imaging. Blinded to any clinical information, two readers evaluated the cardiac and neuroradiologic examinations.

RESULTS

Of 154 imaged ICA, 85 presented with stenosis and 17 were occluded. In 7 patients, the suspected ICA stenosis could not be confirmed by CEMRA. In the remaining 70 patients with ICA stenosis, 34.3% had cerebral lesions (15.7% with a homodynamic pattern,18.6% with territorial infarction). CMR detected MI in 29 (41%) patients, whereas ECG and medical history enabled diagnosis in only 7 (10%) patients.

CONCLUSIONS

ICA stenosis patients have a higher incidence of myocardial scars proving silent MI when detected by contrast-enhanced CMR than clinically expected. Whether the presence and extent of silent MIs detected by CMR affect peri-interventional risk and prognosis of ICA stenosis patients remains to be evaluated in a large patient cohort with long-term follow-up.

[Quantification of microvascular obstruction in acute myocardial infarction using cardiac MRI]

PURPOSE

Microvascular obstruction (MO) and the extent of infarction are important prognostic factors in acute myocardial infarction. Our study aimed to investigate the effect of the time interval between contrast administration and image acquisition on the quantification of microvascular obstruction and myocardial infarction.

MATERIALS AND METHODS

50 consecutive patients with acute myocardial infarction (40 male, mean age 58.1 +/- 11.7 years) treated by percutaneous coronary revascularization resulting in a grade 3 flow according to the thrombolysis in myocardial infarction flow classification were examined on a 1.5 T MR scanner within the first 5 days after infarction. 2, 5, 10, and 20 minutes after I.V. administration of 0.2 mmol/kg per kg body weight of Gadodiamid (Omniscan), GE Healthcare Buchler, Germany), a single shot IR-SSFP sequence (TR 2.4 ms, TE 1.08 ms, TI 180 - 280 ms, FA 50 degrees) covering the entire left ventricle was acquired. Areas of MO and myocardial infarction were measured for all times after contrast injection (p. i.).

RESULTS

MO was detected in 32 of 50 patients two minutes p. i., while 23 patients showed evidence of MO (p = 0.002) 20 min. p. i. In all patients with MO, the extent of MO decreased over time (7.4 +/- 9.0 % of the LV myocardium 2 min. p. i. vs. 2.4 +/- 4.6 % 20 min. p. i. p < 0.0001). The area of myocardial infarction increased from 13.9 +/- 13.5 % 2 min. p. i. to 18.6 +/- 14.2 % 10 min. p. i. (p < 0.0001), and then remained unchanged (18.7 +/- 14.3 % at 20 min. p = 0.57).

CONCLUSION

Our study shows that the time delay between contrast media injection and image acquisition has a significant impact on the delimitable extent of MO and infarct size.

Prevalence, pattern, and functional impact of late gadolinium enhancement in left ventricular hypertrophy due to aortic valve stenosis

PURPOSE

To assess the prevalence and pattern of myocardial late gadolinium enhancement (LGE) and its functional impact on patients with left ventricular hypertrophy caused by aortic valve stenosis.

MATERIALS AND METHODS

Cardiac magnetic resonance imaging of 40 patients (17 female, 23 male, mean age: 76.6 +/- 22.5 years) with known aortic valve stenosis (mean aortic valve area: 89.8 +/- 19.2 mm(2)) and without coronary artery disease was performed at 1.5 T using steady-state free precession sequences for aortic valve planimetry and for the assessment of left ventricular (LV) volumes and mass. Ten to 15 minutes after injection of 0.2 mmol Gd-DTPA per kilogram body weight, inversion-recovery prepared spoiled gradient echo images were acquired in standard long and short axis views to detect areas of LGE.

RESULTS

LGE was observed in 32.5 % (13/40) of our patients. LGE was mainly located in the basal septal and inferior LV segments, and showed a non-ischemic pattern with sparing of the subendocardial region. Patients with LGE showed lower LV ejection fractions (55.5 +/- 13.8 % vs. 69.1 +/- 10.7 %, p = 0.0014), higher LV end-systolic volumes (59.8 +/- 33.3 ml vs. 36.6 +/- 16.0 ml, p = 0.0048), and LV masses (211.0 +/- 13.8 vs. 157.9 +/- 37.5 g, p = 0.0002) compared to patients without LGE.

CONCLUSION

LGE is frequent in patients with hypertrophic left ventricles due to aortic valve stenosis and is associated with worse LV function.

Detektion und Charakterisierung linksventrikulärer Thromben mittels MRT im Vergleich zur transthorakalen Echokardiographie

PURPOSE

Transthoracic echocardiography is the routine diagnostic procedure in assessing patients with left ventricular thrombi, but is limited by the acoustic window and poor contrast between thrombus and adjacent myocardium. This study evaluates the role of cardiac MRI in the detection of left ventricular thrombi in patients with chronic myocardial infarction compared to standard transthoracic echocardiography.

MATERIALS AND METHODS

In 82 patients (55 men and 27 women, age 36 to 79 years, median 59 +/- 11 years) who suffered a myocardial infarction more than 6 months earlier, transthoracic echocardiography and MRI were performed. The MRI protocol included steady state cine imaging (true FISP: TR 3.0 ms, TE 1.5 ms, FA 65 degrees ) in standard long and short axis orientation and contrast-enhanced imaging using a 3D IR-FLASH sequence with long inversion time (TR 4 ms, TE 1.43 ms, FA 10 degrees , TI 300 ms) early, and a 2D IR-FLASH sequence with optimized inversion time (TR 8 ms, TE 4.3 ms, FA 20 degrees , TI 180 - 280 ms) late after administration of gadolinium.

RESULTS

Transthoracic echocardiography depicted 12 thrombi. Contrast-enhanced MRI confirmed these 12 thrombi and detected 23 additional thrombi. With the exception of 2 very small apical thrombi only visible on contrast-enhanced MR images, spherical thrombi were diagnosed by both techniques, whereas only contrast-enhanced MRI was able to visualize mural thrombi. Left ventricular thrombi were more frequently diagnosed in patients with moderate to severe impairment of the left ventricular systolic function, 32/42 (76 %), or in patients with left ventricular aneurysms, 21/24 (84 %).

CONCLUSION

Contrast-enhanced MRI is mostly superior to transthoracic echocardiography in diagnosing mural left ventricular thrombi in patients who had suffered a myocardial infarction. Intracavitary thrombi are more frequently found in patients with impaired regional and global left ventricular function.

["Integrated care"--the Essen concept: organizational strategies in the treatment of acute myocardial infarction]

The German "GKV-Modernisierungsgesetz" offers new opportunities for patient care. The concept of "integrated care" provides organizational structures for an standardized treatment of myocardial infarction by bridging the different sectors of the German health care system. Apart from guideline-based therapy, innovative diagnostic (cardiac MRI) and therapeutic (drug-eluting stents) techniques are implemented in the "integrated care" model as well. The "Herzinfarktverbund Essen" is the first national real world experience of the integrated care concept in the treatment of myocardial infarction.