Remote Zone Extracellular Volume and Left Ventricular Remodeling in Survivors of ST-Elevation Myocardial Infarction

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The natural history and pathophysiological significance of tissue remodeling in the myocardial remote zone after acute ST-elevation myocardial infarction (STEMI) is incompletely understood. Extracellular volume (ECV) in myocardial regions of interest can now be measured with cardiac magnetic resonance imaging. Patients who sustained an acute STEMI were enrolled in a cohort study (BHF MR-MI [British Heart Foundation Magnetic Resonance Imaging in Acute ST-Segment Elevation Myocardial Infarction study]). Cardiac magnetic resonance was performed at 1.5 Tesla at 2 days and 6 months post STEMI. T1 modified Look-Locker inversion recovery mapping was performed before and 15 minutes after contrast (0.15 mmol/kg gadoterate meglumine) in 140 patients at 2 days post STEMI (mean age: 59 years, 76% male) and in 131 patients at 6 months post STEMI. Remote zone ECV was lower than infarct zone ECV (25.6±2.8% versus 51.4±8.9%; P<0.001). In multivariable regression, left ventricular ejection fraction was inversely associated with remote zone ECV (P<0.001), and diabetes mellitus was positively associated with remote zone ECV (P=0.010). No ST-segment resolution (P=0.034) and extent of ischemic area at risk (P<0.001) were multivariable associates of the change in remote zone ECV at 6 months (ΔECV). ΔECV was a multivariable associate of the change in left ventricular end-diastolic volume at 6 months (regression coefficient [95% confidence interval]: 1.43 (0.10–2.76); P=0.036). ΔECV is implicated in the pathophysiology of left ventricular remodeling post STEMI, but because the effect size is small, ΔECV has limited use as a clinical biomarker of remodeling.

Microvascular resistance of the culprit coronary artery in acute ST-elevation myocardial infarction

BACKGROUND. Failed myocardial reperfusion is common and prognostically important after acute ST-elevation myocardial infarction (STEMI). The purpose of this study was to investigate coronary flow reserve (CFR), a measure of vasodilator capacity, and the index of microvascular resistance (IMR; mmHg × s) in the culprit artery of STEMI survivors.

METHODS. IMR (n = 288) and CFR (n = 283; mean age [SD], 60 [12] years) were measured acutely using guide wire–based thermodilution. Cardiac MRI disclosed left ventricular pathology, function, and volumes at 2 days (n = 281) and 6 months after STEMI (n = 264). All-cause death or first heart failure hospitalization was independently adjudicated (median follow-up 845 days).

RESULTS. Myocardial hemorrhage and microvascular obstruction occurred in 89 (42%) and 114 (54%) patients with evaluable T2*-MRI maps. IMR and CFR were associated with microvascular pathology (none vs. microvascular obstruction only vs. microvascular obstruction and myocardial hemorrhage) (median [interquartile range], IMR: 17 [12.0–33.0] vs. 17 [13.0–39.0] vs. 37 [21.0–63.0], P < 0.001; CFR: 1.7 [1.4–2.5] vs. 1.5 [1.1–1.8] vs. 1.4 [1.0–1.8], P < 0.001), whereas thrombolysis in myocardial infarction blush grade was not. IMR was a multivariable associate of changes in left ventricular end-diastolic volume (regression coefficient [95% CI] 0.13 [0.01, 0.24]; P = 0.036), whereas CFR was not (P = 0.160). IMR (5 units) was a multivariable associate of all-cause death or heart failure hospitalization (n = 30 events; hazard ratio [95% CI], 1.09 [1.04, 1.14]; P < 0.001), whereas CFR (P = 0.124) and thrombolysis in myocardial infarction blush grade (P = 0.613) were not. IMR had similar prognostic value for these outcomes as <50% ST-segment resolution on the ECG.

CONCLUSIONS. IMR is more closely associated with microvascular pathology, left ventricular remodeling, and health outcomes than the angiogram or CFR.

TRIAL REGISTRATION. NCT02072850.

FUNDING. A British Heart Foundation Project Grant (PG/11/2/28474), the National Health Service, the Chief Scientist Office, a Scottish Funding Council Senior Fellowship, a British Heart Foundation Intermediate Fellowship (FS/12/62/29889), and a nonfinancial research agreement with Siemens Healthcare.

The index of microvascular resistance correlates with microvascular pathology and is a diagnostic test of myocardial reperfusion in patients with acute ST-elevation myocardial infarction.

Prognostic significance of infarct core pathology revealed by quantitative non-contrast in comparison with contrast cardiac magnetic resonance imaging in reperfused ST-elevation myocardial infarction survivors

AIMS

To assess the prognostic significance of infarct core tissue characteristics using cardiac magnetic resonance (CMR) imaging in survivors of acute ST-elevation myocardial infarction (STEMI).

METHODS AND RESULTS

We performed an observational prospective single centre cohort study in 300 reperfused STEMI patients (mean ± SD age 59 ± 12 years, 74% male) who underwent CMR 2 days and 6 months post-myocardial infarction (n = 267). Native T1 was measured in myocardial regions of interest (n = 288). Adverse remodelling was defined as an increase in left ventricular (LV) end-diastolic volume ≥20% at 6 months. All-cause death or first heart failure hospitalization was a pre-specified outcome that was assessed during follow-up (median duration 845 days). One hundred and sixty (56%) patients had a hypo-intense infarct core disclosed by native T1. In multivariable regression, infarct core native T1 was inversely associated with adverse remodelling [odds ratio (95% confidence interval (CI)] per 10 ms reduction in native T1: 0.91 (0.82, 0.00); P = 0.061). Thirty (10.4%) of 288 patients died or experienced a heart failure event and 13 of these events occurred post-discharge. Native T1 values (ms) within the hypo-intense infarct core (n = 160 STEMI patients) were inversely associated with the risk of all-cause death or first hospitalization for heart failure post-discharge (for a 10 ms increase in native T1: hazard ratio 0.730, 95% CI 0.617, 0.863; P < 0.001) including after adjustment for left ventricular ejection fraction, infarct core T2 and myocardial haemorrhage. The prognostic results for microvascular obstruction were similar.

CONCLUSION

Infarct core native T1 represents a novel non-contrast CMR biomarker with potential for infarct characterization and prognostication in STEMI survivors. Confirmatory studies are warranted. CLINICALTRIALS.

GOV IDENTIFIER

NCT02072850.

Long-term outcomes after adjuvant treatment of sequential versus combination docetaxel with doxorubicin and cyclophosphamide in node-positive breast cancer: BCIRG-005 randomized trial

BACKGROUND

The optimal regimen for adjuvant breast cancer chemotherapy is undefined. We compared sequential to concurrent combination of doxorubicin and cyclophosphamide with docetaxel chemotherapy in women with node-positive non-metastatic breast cancer. We report the final, 10-year analysis of disease-free survival (DFS), overall survival (OS), and long-term safety.

PATIENTS AND METHODS

A total of 3298 women with HER2 nonamplified breast cancer were randomized to doxorubicin and cyclophosphamide every 3 weeks for four cycles followed by docetaxel (AC → T) every 3 weeks for four cycles or docetaxel, doxorubicin, and cyclophosphamide (TAC) every 3 weeks for six cycles. The patients received standard radiotherapy and endocrine therapy and were followed up for 10 years with annual clinical evaluation and mammography.

RESULTS

The 10-year DFS rates were 66.5% in the AC → T arm and 66.3% in the TAC arm (P = 0.749). OS was 79.9% in the AC → T arm and 78.9% in the TAC arm (P = 0.506). TAC was associated with higher rates of febrile neutropenia, although G-CSF primary prophylaxis greatly reduced this risk. AC → T was associated with a higher rate of myalgia, hand-foot syndrome, fluid retention, and sensory neuropathy.

CONCLUSION

This 10-year analysis of the BCIRG-005 trial confirmed that the efficacy of TAC was not superior to AC → T in women with node-positive early breast cancer. The toxicity profiles differ between arms and were consistent with previous reports. The TAC regimen with G-CSF support provides shorter adjuvant treatment duration with less toxicity.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT00312208.

Safety of guidewire-based measurement of fractional flow reserve and the index of microvascular resistance using intravenous adenosine in patients with acute or recent myocardial infarction

AIMS

Coronary guidewire-based diagnostic assessments with hyperemia may cause iatrogenic complications. We assessed the safety of guidewire-based measurement of coronary physiology, using intravenous adenosine, in patients with an acute coronary syndrome.

METHODS

We prospectively enrolled invasively managed STEMI and NSTEMI patients in two simultaneously conducted studies in 6 centers (NCT01764334; NCT02072850). All of the participants underwent a diagnostic coronary guidewire study using intravenous adenosine (140 μg/kg/min) infusion for 1-2 min. The patients were prospectively assessed for the occurrence of serious adverse events (SAEs) and symptoms and invasively measured hemodynamics were also recorded.

RESULTS

648 patients (n=298 STEMI patients in 1 hospital; mean time to reperfusion 253 min; n=350 NSTEMI in 6 hospitals; median time to angiography from index chest pain episode 3 (2, 5) days) were included between March 2011 and May 2013. Two NSTEMI patients (0.3% overall) experienced a coronary dissection related to the guidewire. No guidewire dissections occurred in the STEMI patients. Chest symptoms were reported in the majority (86%) of patient's symptoms during the adenosine infusion. No serious adverse events occurred during infusion of adenosine and all of the symptoms resolved after the infusion ceased.

CONCLUSIONS

In this multicenter analysis, guidewire-based measurement of FFR and IMR using intravenous adenosine was safe in patients following STEMI or NSTEMI. Self-limiting symptoms were common but not associated with serious adverse events. Finally, coronary dissection in STEMI and NSTEMI patients was noted to be a rare phenomenon.

Fractional flow reserve (FFR) versus angiography in guiding management to optimise outcomes in non-ST segment elevation myocardial infarction (FAMOUS-NSTEMI) developmental trial: cost-effectiveness using a mixed trial- and model-based methods

Background

In the Fractional flow reserve (FFR) versus angiography in guiding management to optimise outcomes in non-ST elevation myocardial infarction (FAMOUS) clinical trial, FFR was shown to significantly reduce coronary revascularisation, compared to visual interpretation of standard coronary angiography without FFR. We estimated the cost-effectiveness from a UK National Health Service perspective, based on the results of FAMOUS.

Methods

A mixed trial- and model-based approach using decision and statistical modelling was used. Within-trial (1-year) costs and QALYs were assembled at the individual level and then modelled on subsequent management strategy [coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI) or medical therapy (MT)] and major adverse coronary events (death, MI, stroke and revascularisation). One-year resource uses included: material, hospitalisation, medical, health professional service use and events. Utilities were derived from individual EQ5D responses. Unit costs were derived from the literature. Outcomes were extended to a lifetime on the basis of MACE during the 1st year. Costs and QALYs were modelled using generalized linear models whilst MACE was modelled using logistic regression. The analysis adopted a payer perspective. Costs and outcomes were discounted at 3.5 %.

Results

Costs were related to the subsequent management strategy and MACE whilst QALYs were not. FFR led to a modest cost increase, albeit an imprecise increase, over both the trial [£112 (−£129 to £357)] and lifetime horizons [£133 (−£199 to £499)]. FFR led to a small, albeit imprecise, increase in QALYs over both the trial [0.02 (−0.03 to 0.06)] and lifetime horizons [0.03 (−0.21 to 0.28)]. The mean ICER was £7516/QALY and £4290/QALY over the trial and lifetime horizons, respectively. Decision remained high; FFR had 64 and 59 % probability of cost-effectiveness over trial and lifetime horizons, respectively.

Conclusions

FFR was cost-effective at the mean, albeit with considerable decision uncertainty. Uncertainty can be reduced with more information on long-term health events.

Electronic supplementary material

The online version of this article (doi:10.1186/s12962-015-0045-9) contains supplementary material, which is available to authorized users.