Erik Christensen

Bio: Erik Christensen is an academic researcher. The author has contributed to research in topics: Heart failure & Angiotensin-converting enzyme. The author has an hindex of 7, co-authored 7 publications receiving 584 citations.

64-multislice detector computed tomography coronary angiography as potential alternative to conventional coronary angiography: a systematic review and meta-analysis.

Abstract: Aims To evaluate the diagnostic accuracy of 64-slice multi-detector computed tomography coronary angiography (64-SCTA) compared with the standard reference conventional coronary angiography (CCA). Methods and results Based on a systematic search, 27 studies including 1740 patients were eligible for meta-analyses. Nineteen studies examined native coronary arteries ( n = 1,251), four studies examined coronary artery by-pass grafts (CABG) ( n = 271), and five studies examined coronary stents ( n = 270). Overall 18 920 segments were assessable and 810 (4%) were unassessable. The prevalence of native coronary artery stenosis in per-segment (19 studies) and per-patients (13 studies) populations were 19 and 57.5% respectively. Accuracy tests with 95% confidence intervals comparing 64-SCTA vs. CCA showed that sensitivity, specificity, positive predictive and negative predictive values for native coronary arteries were 86(85–87), 96(95.5–96.5), 83, and 96.5% by per-segment analysis; 97.5(96–99), 91(87.5–94), 93, and 96.5% by per-patient analysis; 98.5(96–99.5), 96(93.5–97.5), 92 and 99% for CABGs; 80(70–88.5), 95(92–97), 80, and 95% for stent restenosis; and 87(86.5–88), 96(95.5–96.5), 83.5, and 97% by overall per-segment analysis. Conclusion The high diagnostic accuracy of 64-SCTA validates this non-invasive technique as a potential alternative to CCA in carefully selected populations suspected for coronary stenosis.

Impact of obesity as a mortality predictor in high-risk patients with myocardial infarction or chronic heart failure: a pooled analysis of five registries

Abstract: Aims To explore the influence of obesity on prognosis in high-risk patients with myocardial infarction (MI) or heart failure (HF). Methods and results Individual data of 21 570 consecutively hospitalized patients from five Danish registries were pooled together. After a follow-up of 10.4 years, all-cause mortality using multivariate model and adjusted hazard ratios (HR) with 95% confidence intervals were calculated. Compared with normal weight [body mass index (BMI) 18.5–24.9 kg/m2], obesity class II (BMI ≥ 35 kg/m2) was associated with increased risk of death in patients with MI but not HF \[HR = 1.23 (1.06–1.44), P = 0.006 and HR = 1.13 (0.95–1.36), P = 0.95\] ( P -value for interaction = 0.004). Obesity class I (BMI 30–34.9 kg/m2) was not associated with increased risk of death in MI or HF [HR = 0.99 (0.92–1.08) and 1.00 (0.90–1.11), P > 0.1]. Pre-obesity (BMI 25–29.9 kg/m2) was associated with decreased death risk in MI but not HF \[HR = 0.91 (0.87–0.96), P = 0.0006 and 1.04 (0.97–1.12), P = 0.34\] ( P -value for interaction = 0.007). Underweight (BMI < 18.5 kg/m2) patients were in increased death risk regardless of MI or HF [HR = 1.54 (1.35–1.75) and 1.37 (1.18–1.59), P < 0.001]. Conclusion In patients with MI but not HF, the relationship between BMI and mortality is U-shaped with highest mortality in underweight and obese class II, but lowest in the other BMI classes.

A systematic review: effect of angiotensin converting enzyme inhibition on left ventricular volumes and ejection fraction in patients with a myocardial infarction and in patients with left ventricular dysfunction.

Abstract: Background and aim To summarize and quantify results of echocardiographic studies examining the effect of angiotensin converting enzyme (ACE) inhibition on left ventricular remodelling in patients with acute myocardial infarction (MI) and in patients with left ventricular systolic dysfunction (LVSD). Methods Systematic review of the literature and meta-analysis of eligible studies providing data on end-diastolic and end-systolic volumes and left ventricular ejection fraction (LVEF) were performed. Results Data from 16 eligible studies were meta-analysed. The results of studies including patients with MI and preserved LVEF (>45%) showed no significant benefit of ACE inhibition. Results of studies/subgroups with mean LVEF ≤45% demonstrated significant differences in diastolic and systolic volumes of 3.0 (0.1, 6.0) ml and 2.25 (0.04, 4.4) ml in short-term (4–14 weeks) follow-up in favour of ACE inhibitor, p=0.041 and p=0.046 respectively. In the long-term (6–12 months) follow-up, the differences in diastolic and systolic volumes were 4.2 (0.98, 7.4) ml and 3.3 (0.9, 5.8) ml in favour of ACE inhibitor, p=0.01 and p=0.007 respectively. LVEF improved in both short and long-term follow-up, p=0.034 and p=0.021, respectively. Conclusion Chronic use of ACE inhibition has a small but sustained and beneficial effect on remodelling in patients with myocardial infarction and patients with chronic left ventricular dysfunction.

Effect of beta-blocker therapy on functional status in patients with heart failure--a meta-analysis.

Abstract: Background: The results of randomised control trials (RCTs) evaluating the effect of beta-blockers on functional status in patients with chronic heart failure are conflicting. Aim: To perform a systematic review and meta-analysis of RCTs evaluating the effect of beta-blockers on New York Heart Association (NYHA) classification and exercise tolerance in chronic heart failure. Methods and results We selected 28 RCTs evaluating beta-blocker versus placebo in addition to ACE inhibitor therapy. Combined results of 23 RCTs showed that beta-blockers improved NYHA class by at least one class with odds ratio (OR) 1.80 (1.33–2.43) p<0.0001. Meta-analysis of 10 RCTs showed a significant prolongation of exercise time by 44.19 (6.62–81.75) s p=0.021. Combining 8 RCTs evaluating the maximal peak oxygen uptake and 9 RCTs evaluating 6-min walk distance showed that beta-blockers had no significant effect compared with placebo, p=0.484, and p=0.730, respectively. Combined results of the 23 RCTs showed significant reducing effect on all cause mortality with OR=0.69 (0.59–0.82) p<0.0001. Conclusion: Chronic use of a beta-blocker in conjunction with ACE inhibitor therapy improves dyspnoea and prolongs exercise tolerance time, but has no significant effect on 6-min walk test or maximal oxygen uptake in patients with heart failure.

Evaluation of aortic valve stenosis by cardiac multislice computed tomography compared with echocardiography: a systematic review and meta-analysis.

Abstract: BACKGROUND AND AIM OF THE STUDY It has not yet been established whether multi-slice computed tomography (MSCT) is reliable for the quantification of aortic valve area (AVA) in patients with aortic valve stenosis (AVS) and simultaneously for assessment of the coronary anatomy. The study aim, via a systematic literature review and meta-analysis, was to explore whether MSCT is a reliable method for AVA quantification, and simultaneously to assess the coronary anatomy in patients with AVS. METHODS A comprehensive systematic literature search and meta-analysis was conducted that included 14 studies totaling 470 patients. The meta-analysis was carried out to examine the reliability of MSCT compared to transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE). Seven studies including 266 patients with AVS were also eligible for a secondary analysis to compare the accuracy of MSCT with invasive coronary angiography. RESULTS The AVA was measured by MSCT and TTE in all 14 studies, and by TEE in four studies. The results of the meta-analyses showed that planimetry by MSCT overestimated the AVA, with a bias of 0.08 (95% CI 0.04, 0.13) cm2) (p = 0.0001) compared to TTE. The MSCT measurement was concordant with planimetry by TEE, with a small bias of -0.02 (95% CI -0.16, 0.11) cm2 (p = 0.71). MSCT, when compared to invasive angiography for the detection of significant coronary stenosis, showed sensitivity, specificity and diagnostic odds ratio of 95.5% (95% CI 88-99), 81% (95% CI 75-86)%, and 53 (95% CI 19-147), respectively. CONCLUSION MSCT is a reliable method for the quantification of AVA, and represents a promising technique for the combined evaluation of aortic valve morphology and coronary artery disease.

Oxidative stress and left ventricular remodelling after myocardial infarction

Abstract: In acute myocardial infarction (MI), reactive oxygen species (ROS) are generated in the ischaemic myocardium especially after reperfusion. ROS directly injure the cell membrane and cause cell death. However, ROS also stimulate signal transduction to elaborate inflammatory cytokines, e.g. tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta and -6, in the ischaemic region and surrounding myocardium as a host reaction. Inflammatory cytokines also regulate cell survival and cell death in the chain reaction with ROS. Both ROS and inflammatory cytokines are cardiodepressant mainly due to impairment of intracellular Ca(2+) homeostasis. Inflammatory cytokines stimulate apoptosis through a TNF-alpha receptor/caspase pathway, whereas Ca(2+) overload induced by extensive ROS generation causes necrosis through enhanced permeability of the mitochondrial membrane (mitochondrial permeability transition). Apoptosis signal-regulating kinase-1 (ASK1) is an ROS-sensitive, mitogen-activated protein kinase kinase kinase that is activated by many stress signals and can activate nuclear factor kappaB and other transcription factors. ASK1-deficient mice demonstrate that the ROS/ASK1 pathway is involved in necrotic as well as apoptotic cell death, indicating that ASK1 may be a therapeutic target to reduce left ventricular (LV) remodelling after MI. ROS and inflammatory cytokines activate matrix metalloproteinases which degrade extracellular matrix, causing a slippage of myofibrils and hence LV dilatation. Consequently, collagen deposition is increased and tissue repair is enhanced with myocardial fibrosis and angiogenesis. Since the extent of LV remodelling is a major predictor of prognosis of the patients with MI, the therapeutic approach to attenuating LV remodelling is critically important.

Noninvasive Coronary Artery Imaging Magnetic Resonance Angiography and Multidetector Computed Tomography Angiography: A Scientific Statement From the American Heart Association Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention, and the Councils on Clinical Cardiology and Cardiovascular Disease in the Young

Abstract: Since the early 1960s, selective x-ray coronary angiography has provided the only means of visualizing the coronary arterial system in vivo. However, it has several disadvantages. First, the incidence, albeit relatively low, of so-called major adverse events (death, myocardial infarction, or stroke) during or within 24 hours of selective coronary angiography is reported to be 0.2% to 0.3%, and the incidence of so-called minor complications (most of which are related to problems with the peripheral vessels through which catheters are inserted) is roughly 1% to 2%.1–3 Second, x-ray coronary angiography is accompanied by a modest amount of discomfort, because the placement of catheters is invasive. Third, it is expensive: the required equipment is costly, and the performance of the procedure necessitates considerable time and skill of highly trained physicians and support personnel. Last, the information obtained via catheter-based coronary angiography pertains to the coronary arterial lumen alone. As a result, alternative methods of visualizing the coronary arterial system that would allow one to avoid these disadvantages are desirable. Over the past 15 years, substantial advances have been made in noninvasive cardiac imaging in general and in visualization of the coronary arteries in particular. Magnetic resonance angiography (MRA) of the coronary arteries was advanced in the early 1990s with the development of high-speed gradient techniques and dedicated cardiac coils. The primary advantage of this technique is the patient’s lack of exposure to ionizing radiation or iodinated contrast media. Coronary MRA may also be combined with other magnetic resonance (MR) imaging techniques for assessment of cardiac function, structure, blood flow, and viability.4 Electron-beam computed tomography (CT) with iodinated contrast injection was originally used to perform coronary angiograms, but this has been supplanted by multidetector CT (MDCT) scanners that have 16 to 256 rows of detectors. MDCT can provide visually compelling …

Expert consensus for multi-modality imaging evaluation of cardiovascular complications of radiotherapy in adults: a report from the European Association of Cardiovascular Imaging and the American Society of Echocardiography.

Abstract: Cardiac toxicity is one of the most concerning side effects of anti-cancer therapy. The gain in life expectancy obtained with anti-cancer therapy can be compromised by increased morbidity and mortality associated with its cardiac complications. While radiosensitivity of the heart was initially recognized only in the early 1970s, the heart is regarded in the current era as one of the most critical dose-limiting organs in radiotherapy. Several clinical studies have identified adverse clinical consequences of radiation-induced heart disease (RIHD) on the outcome of long-term cancer survivors. A comprehensive review of potential cardiac complications related to radiotherapy is warranted. An evidence-based review of several imaging approaches used to detect, evaluate, and monitor RIHD is discussed. Recommendations for the early identification and monitoring of cardiovascular complications of radiotherapy by cardiac imaging are also proposed.