Mechanisms of myocardial infarction without obstructive coronary artery disease

Cardiovascular Magnetic Resonance May Avoid Unnecessary Coronary Angiography in Patients With Unexplained Left Ventricular Systolic Dysfunction: A Retrospective Diagnostic Pilot Study

BACKGROUND

Coronary angiography (CA) is usually performed in patients with reduced left ventricular ejection fraction (LVEF) to search ischemic cardiomyopathy. Our aim was to examine the agreement between CA and cardiovascular magnetic resonance (CMR) imaging among a cohort of patients with unexplained reduced LVEF, and estimate what would have been the consequences of using CMR imaging as the first-line examination.

METHODS

Three hundred five patients with unexplained reduced LVEF of ≤45% who underwent both CA and CMR imaging were retrospectively registered. Patients were classified as CMR⁺ or CMR^- according to presence or absence of myocardial ischemic scar, and classified CA⁺ or CA^- according to presence or absence of significant coronary artery disease.

RESULTS

CMR⁺ (n = 89) included all 54 CA⁺ patients, except 2 with distal coronary artery disease in whom no revascularization was proposed. Among the 247 CA^- patients, 15% were CMR⁺. CMR imaging had 96% sensitivity, 85% specificity, 99% negative predictive value, and 58% positive predictive value for detecting CA⁺ patients. Revascularization was performed in 6.5% of the patients (all CMR⁺). Performing CA only for CMR⁺ patients would have decreased the number of CAs by 71%.

CONCLUSIONS

In reduced LVEF, performing CA only in CMR⁺ patients may significantly decrease the number of unnecessary CAs performed, without missing any patients requiring revascularization.

MINOCA: The caveat of absence of coronary obstruction in myocardial infarction

AIMS

Whether patients with MINOCA (myocardial infarction with non-obstructive coronary arteries) have better outcomes than patients with obstructive coronary artery disease remains contradictory. The current study focussed on the clinical profile and prognosis of MINOCA patients.

METHODS AND RESULTS

We performed a retrospective analysis of patients with acute coronary syndrome (ACS) admitted to the Isala hospital in Zwolle, the Netherlands, between 2006 and 2014. A total of 7693 patients were categorized into three groups: MINOCA, single-vessel obstructive ACS (SV-ACS), and multi-vessel obstructive ACS (MV-ACS). MINOCA patients (5.2% of the total population) were more likely to be female (51.5% vs. 30.3% and 26.0% in SV-ACS and MV-ACS, respectively, p < 0.001 for both). The prevalence of risk factors in the MINOCA group was in between the SV-ACS and MV-ACS groups. Logistic regression revealed a lower odds of dying in SV-ACS (odds ratio (OR) = 0.70 (p = 0.04)) and a similar odds in MV-ACS (OR = 0.88, p = 0.45) compared to MINOCA.

CONCLUSIONS

Patients with MINOCA show an 'intermediate' risk profile with mortality rates in between those of both ACS groups. Hence, MINOCA should be recognised as a potential risk factor for mortality, requiring adequate treatment and follow-up.

Patients with non-obstructive coronary artery disease admitted with acute myocardial infarction carry a better outcome compared to those with obstructive coronary artery disease

Background

The characterization of patients who have acute myocardial infarction (AMI) and insignificant coronary stenosis is unclear.

Aim

The present study aimed to investigate the clinical profile, in-hospital and 3-month outcome of AMI patients with insignificant coronary stenosis in comparison with those with significant disease.

Methods

This prospective observational study included 200 consecutive patients admitted with AMI. Group I (100 patients) included patients with insignificant CAD (all lesions <50% stenosis). Group II (100 patients) included patients with one or more lesions >70% stenosis. Patients with previous CABG were excluded. Patients with significant CAD had successful total revascularization.

Results

Patients with insignificant CAD were significantly younger (61 vs. 67 years, p < 0.001), more likely to be females (41% vs. 23%, p = 0.006), less likely to smoke (p = 0.006), less likely to have diabetes mellitus (p < 0.001), and less likely to have history of CAD (p = 0.042) or prior PCI (p = 0.037). They were also less likely to have typical anginal pain at presentation (61% vs 91%, p < 0.001), less likely to have heart failure at presentation (9% vs 30%, p < 0.001), less likely to have ischemic ST-segment changes on presentation (10% vs 46%, p < 0.001), lower peak troponin (p < 0.001) and CK-MB levels (p < 0.001), with lower LDL-C (p = 0.006), and higher HDL-C level (p = 0.020). They were less likely to be treated with b-blockers (p = 0.002), ACEI/ARBS (p = 0.007), and higher rates of calcium channel blocker therapy (p < 0.001). They had lower prevalence of major adverse clinical events at follow-up (readmission for ACS (p = 0.009), need for revascularization (p = 0.035), recurrent chest pain (p = 0.009), and cardiogenic shock (p = 0.029).

Conclusion

Patients with AMI and insignificant CAD have different clinical profile and outcome compared to those with significant disease.

The affection of the disturbance of the hydrodynamics of blood in case of stress on pathological increase of level of low density lipoproteins in blood. The formation of cylindrical plaques, and their participation in the development of acute ischemic disorders of heart and brain

In this article is given the new insight about the affection of stress on the increase of level of low density lipoproteins (LDL) in the blood, which is connected with the disturbance of hydrodynamics in the bloodstream, the attention was paid to the cylindrical cholesterol plaque, and it's classification. The disturbance of hydrodynamics of blood under the stress leads to the formation of a cylindrical cholesterol plaque, which repeats the contour of the vessel, and leads to the ischemic disorders of the heart and brain. The cylindrical cholesterol plaque goes through several stages of development: friable, yielding, dense, old. In the case of destruction of friable, fresh cholesterol plaque, releases a big quantity of low-density lipoproteins. This leads to the pathological increase of level of LDL in the blood. In the case of long disturbance of hydrodynamics, occurs the formation of strong links between low-density lipoproteins. Yielding cholesterol plaque is formed. Further maturation of cylindrical cholesterol plaque, leads to it's densifying and damage. We may emphasize, that short periods of strong contraction and expansion of vessels lead to the increase of level of LDL in the blood. Self-dependent restoration of normal level of LDL in blood occurs in the case of restoration of pressure in the limits of numbers, which are specific for particular person, and which don't exceed the physiological standard. Among patients with long duration of stress, the duration of vasospasm increases. LDL, without having a possibility to crumble, begin to stick together and form the yielding cylindrical plaque. It is characterized by having of not so strong connection with the vascular wall, and maintains only at the expanse of iteration of the vascular wall, it has cylindrical shape, is elastic and yellow. The thickness and length of walls depends on the degree of cross-clamping during the time of formation of yielding cylindrical plaque. In the case of stopping of spasm, yielding cylindrical plaque can resolve slowly. Among hypotensive and individuals, which have normal pressure, the increase of level of LDL isn't noted. There aren't such investigations, where such link was noted. The increasing of level of LDL among these people (especially under the stress) can say about cases of short-term increase of pressure, which could be unnoticed. These patients require pressure monitoring and, accordingly, the adjustment of the state of stress and anger.

Changes in left ventricular function after spontaneous coronary artery dissection

BACKGROUND

Spontaneous healing of spontaneous coronary artery dissection (SCAD) and left ventricular ejection fraction (LVEF) recovery is frequently observed clinically. However, LVEF on presentation and follow-up imaging has not been described.

HYPOTHESIS

We hypothesize that LV dysfunction improves at follow-up after initial SCAD presentation.

METHODS

We included patients with nonatherosclerotic SCAD prospectively followed at Vancouver General Hospital, who had baseline assessment of LVEF and wall-motion abnormality (WMA) during their index presentation. A subset of these patients had repeat assessment of their ventricular function at follow-up. We compared the baseline LVEF and WMA with follow-up assessments and correlated to long-term cardiovascular outcomes.

RESULTS

We included 277 SCAD patients who had baseline ventricular assessment performed. The average age was 52.4 ± 9.4 years, and 90.3% were female. All presented with myocardial infarction (24.2% STEMI, 75.8% NSTEMI). At baseline, the mean LVEF was 55.6% ± 9.1% and 72/277 (26.0%) had LVEF <50%. The presence of WMA was observed in 237/277 (85.6%) cases. Of 164 patients with repeat assessments, the baseline LVEF was 54.6% ± 9.2%, with improvement to 60.7% ± 7.2% at follow-up (P < 0.001). Baseline LVEF of <50% was observed in 29.9%, but only 6.7% had LVEF <50% at follow-up (P < 0.001). Baseline WMA was observed in 87.2% but decreased to 44.5% at follow-up (P < 0.001). Multivariable analysis showed that presentation with STEMI (odds ratio [OR]: 2.71, P = 0.001), troponin I >50 µg/L (OR: 1.02, P = 0.005), and SCAD involvement of the LAD (OR: 2.5, P = 0.002) were independent predictors of baseline LVEF <50%.

CONCLUSIONS

In our large, prospectively followed SCAD cohort, the majority of patients presented with WMA and had relatively normal LVEF. Over half had subsequent normalization of WMA and LVEF on follow-up assessment.

Optical Coherence Tomography in the Diagnosis and Management of Spontaneous Coronary Artery Dissection

Spontaneous coronary artery dissection (SCAD) is an infrequent condition that has been underdiagnosed and misdiagnosed. The use of intracoronary imaging with intravascular ultrasound or optical coherence tomography enables the accurate diagnosis of this challenging condition. Diagnostic and management algorithms have been proposed to improve the diagnosis and therapeutic stratification of SCAD. Optical coherence tomography has superior spatial resolution than intravascular ultrasound, and is instrumental in the diagnosis of SCAD cases where angiographic findings are ambiguous for confirming SCAD. Understanding the role and appropriate and careful use of this technology is expected to improve the diagnosis of SCAD, and also improve outcomes with percutaneous coronary intervention, when clinically indicated.