Right Coronary Artery Distribution Research Articles

Unique case of duplex interventricular branching from the left coronary artery

We report a rare morphological variant of the left coronary artery in this case of a female embalmed cadaver, where in the heart was nourished by double anterior and posterior interventricular arteries. These were branches of the left coronary artery and it was also observed that distribution of right coronary artery was very limited. The deceased may have been without symptoms in her life, but a prior knowledge of this kind of presentation would be very much informative to the interventional cardiologist and cardiothoracic surgeons in their protocol of treatment. This has implications for the coronary angiography and subsequent management of the ischemic heart disease.

The accuracy of distribution of non-ST elevation electrocardiographic changes in localising the culprit vessel in non-ST elevation myocardial infarction.

IntroductionST-segment elevation distribution on electrocardiogram (ECG) in patients presenting with ST-elevation myocardial infarction (STEMI) accurately localises the culprit vessel. However, the utility of the ECG changes in localising the coronary culprit territory in the setting of non-ST segment elevation myocardial infarction (NSTEMI) is not well established.Material and methodsThis study included patients presenting with NSTEMI, who had dynamic non-ST elevation ischaemic changes in one or more ECG leads and underwent percutaneous coronary intervention (PCI) in a single vessel between October 2011 and November 2017 in a single university hospital institution. The accuracy, sensitivity, and specificity of the distribution of ECG changes in localising the culprit vessel were calculated.ResultsThere was a total of 82 patients included in this study, who received PCI to the left anterior descending (LAD), right coronary artery (RCA), and left circumflex (LCX), in 43.9%, 24.4%, and 31.7%, respectively; 51% were male. In this cohort, sensitivity of ECG in localising single-culprit-vessel NSTEMI was 41.5%. The overall accuracy of ECG changes was 50.0%, 72.0%, and 70.0% in LAD, RCA, and LCX distribution, respectively. The sensitivity and specificity were 72.2% and 32.6% in LAD distribution, 20% and 88.7% in RCA distribution, and 15.4% and 82.1% in LCX distributions, respectively.ConclusionsIschaemic non-ST elevation ECG changes had modest accuracy in localising the culprit vessel in patients with PCI-treated NSTEMI. These changes were more sensitive in LAD distribution and more specific in RCA and LCX distributions.

Effect of infarct site on the clinical endpoints of thrombolytic-treated ST-elevation myocardial infarction

IntroductionSome studies suggest better outcomes after the use of thrombolytics in inferior ST-elevation myocardial infarction (STEMI) compared to other locations. The goal of this study is to compare the clinical endpoints of thrombolytic-treated STEMI based on coronary artery distribution. MethodsThe study population was extracted from the 2014 Nationwide Readmissions Data using the International Classification of Diseases, Ninth Revision, Clinical Modifications codes for STEMI, thrombolytic infusion, and complications of STEMI. Primary study endpoints included in-hospital all-cause mortality, length of hospital stay (LOS), cardiogenic shock, and mechanical complications of STEMI. ResultsA principal diagnosis of thrombolytic-treated STEMI was identified for in 1231 patients (mean age 61.5 years; 26.5% female). Four hundred and thirty-one STEMIs occurred in the left anterior descending (LAD) artery distribution, 124 in the left circumflex (LCX) artery distribution, and 676 in the right coronary artery (RCA) distribution. In comparison to the LAD and LCX distributions, thrombolytic-treated STEMIs in the RCA distribution were associated with lower mortality (6.5% with LAD, 5.7% with LCX, and 3.6% with RCA; p = 0.02), fewer cardiogenic shock (12.3% with LAD, 12.1% with LCX, and 7.7% with RCA; p = 0.01), and shorter LOS (4.5 days with LAD, 3.9 with LCX, and 3.6 days with RCA; p < 0.01). Mechanical complications showed no significant difference based on coronary distribution (2.3% with LAD, 3.2% with LCX, and 1.2% with RCA; p = 0.17). ConclusionsThrombolytic-treated STEMIs in the RCA distribution were associated with lower in-hospital all-cause mortality, cardiogenic shock, and shorter LOS. Mechanical complications were not different based on coronary distribution.

Isolated Permanent Right Ventricular Assistance Using the HVAD Continuous-Flow Pump

Acute isolated right ventricular (RV) failure from myocardial infarction is a rare scenario. To date, there are no assist devices developed or approved for permanent isolated right heart support. We report on the successful implantation of a HeartWare HVAD as an isolated RV assist in a patient who suffered extended RV myocardial infarction after iatrogenic dissection of the right coronary artery. No manipulations of the system were required to adapt the assist device to the pulmonary circulation.

Myocardial perfusion changes in patients irradiated for left-sided breast cancer and correlation with coronary artery distribution

Purpose: To evaluate postradiation regional heart perfusion changes with single photon emission tomography (SPECT) myocardial perfusion imaging in 69 patients treated with tangential photon beams radiation therapy (RT) for left-sided breast cancer. To correlate SPECT changes with percent irradiated left ventricle (LV) volume and risk factors for coronary artery disease (CAD). Methods and Materials: Rest SPECT of the LV was acquired pre-RT and at 6-month intervals post-RT. The extent of defects (%) with a severity > 1.5 standard deviations below the mean was quantitatively analyzed for the distributions of the left anterior descending (LAD) artery, left circumflex (LCX) artery, and right coronary artery (RCA) based on computer assisted polar map reconstruction (i.e., bull’s-eye-view). Changes in perfusion were correlated with percent irradiated LV receiving > 25 Gy (range 0–32%). Data on patient- and treatment-related factors were collected prospectively (e.g., cardiac premorbidity, risk factors for CAD, chemotherapy, and hormonal treatment). Results: In the LAD distribution, there were increased perfusion defects at 6 months (median 11%; interquartile range 2–23) compared with baseline (median 5%; interquartile range 1–14) ( p < 0.001). There were no increases in perfusion defects in the LCX or RCA distributions. In multivariate analysis, the SPECT perfusion changes in the LAD distribution at 6 months were independently associated with percent irradiated LV ( p < 0.001), hormonal therapy ( p = 0.005), and pre-RT hypercholesterolemia ( p = 0.006). The SPECT defects in the LAD distribution at 12 and 18 months were not statistically different from those at 6 months. The perfusion defects in the LAD distribution were limited essentially to the regions of irradiated myocardium. Conclusion: Tangential photon beam RT in patients with left-sided breast cancer was associated with short-term SPECT defects in the vascular distribution corresponding to the radiation portals. Factors related to the extent of perfusion defects included the percent irradiated LV, hormonal treatment, and pre-RT hypercholesterolemia.

Is ST elevation the only electrocardiographic response of the ischemic right ventricle?

Right ventricular (RV) infarction is frequently associated with transient ST elevation in right precordial leads 1,2. Studies of patients with an inferior infarction have shown that right precordial ST elevation is predictive of a proximal right coronary artery (RCA) occlusion 3, and that the duration of the ST elevation is predictive of the extent of early RV dysfunction 4. The spectrum of electrocardiographic response to ventricular ischemia is well described in the left coronary distribution 5–7 but not in the RCA distribution. Stenosis of the proximal RCA before the major RV branches is uniformly associated with exercise-induced right precordial ST elevation 8–10. Proximal RCA lesions have also been associated with a reduction in RV ejection fraction during exercise and during balloon occlusion. 11,12 Two studies of 8 and 13 patients undergoing RCA angioplasty showed right precordial ST elevation, but did not report the occurrence of right precordial ST depression 13,14. This study was performed prospectively to determine the electrocardiographic response in V 4R in consecutive patients undergoing coronary angioplasties, using angioplasty as a model of reversible ischemia. We hypothesized that ischemia during proximal RCA angioplasty would be similar to exercise-induced ischemia—that is, ST elevation and not ST depression would be seen in the right precordial leads.

Estimation of the functional and anatomic extent of myocardial infarction using magnetic resonance imaging

This study assesses magnetic resonance (MR) imaging for the evaluation of both the functional and anatomic extent of damage to the left ventricle (LV) from myocardial infarction (MI). This was accomplished by blinded region-of-interest analysis of 36 MR examinations (orthogonal-transaxial, electrocardiographically-gated, multiphasic, single spin-echo) for determination of ejection fraction (EF) and relative MI volume (i.e., percent of total LV myocardial volume). Comparison of the results was then made with a measure of global residual LV function (i.e., score quotient or SQ) derived from segmental scoring of LV wall motion on a two-dimensional echocardiogram (Echo) and with an EF value from a left ventriculogram (LVG), both performed relatively concurrently with MR. Significant ( p < 0.01) overall correlations were noted between MR-EF and both Echo-SQ ( r = 0.56) and LVG-EF ( r = 0.78), and these relationships were relatively stronger when MI was located in the right coronary artery (RCA) than when it was found in the left anterior descending (LAD) distribution (e.g., MR-EF compared with LVG-EF: r = 0.87, p < 0.05 for RCA; and r = 0.48, p = NS for LAD). The best expression of relative MI volume appeared to be based upon absolute volume of regionally-thinned LV wall multiplied by a correction factor for its residual contractility and then the addition of a volume correcting for the amount of regional wall thinning by necrosis (i.e., “total-Fxn” MI volume). The overall correlations between “total-Fxn” MI volume and both Echo-SQ ( r = 0.73) and LVG-EF ( r = 0.86) were significant ( p < 0.01), but were relatively stronger when MI was located in the LAD ( r = 0.64, p < 0.05, and r = 0.93, p < 0.05, respectively) rather than in the RCA distribution ( r = 0.02, p = NS, and r = 0.47, p = NS, respectively). Regional differences in the results are probably at least partially related to limitations with orthogonal-transaxial imaging. For the evaluation of both functional and anatomic extent of MI, MR imaging (transaxial, multiphasic) is valuable, but its relative value varies between regions of the LV.

Segmental evaluation of left ventricular wall motion after myocardial infarction: Magnetic resonance imaging versus echocardiography

To assess relative capabilities of magnetic resonance (MR) imaging and two-dimensional echocardiography (2DE) for evaluating regional contractile dysfunction in the left ventricle after a myocardial infarction, results from 22 concurrent MR (orthogonal-transaxial, ECG-gated, multiphasic, single-spin echo) and 2DE examinations were compared. By means of the same 11-segment LV description, MR and 2DE examinations were independently scored segment by segment for residual wall motion (point scores: 2 = normal, 1 = hypokinesia, 0 = akinesia, and −1 = dyskinesia). Significant correlation between MR and 2DE scoring was found throughout most of the left anterior descending (LAD) distribution, but right coronary artery (RCA) distribution (i.e., middle-posterior segment not well seen) could not be fully evaluated by MR imaging. When cumulative scores for the 10 segments mutually evaluated were used to derive measures of global residual LV function (i.e., score quotient [SQ] = accumulated points ÷ 20 total possible points), MR SQ correlated well overall with both 2DE SQ ( r = 0.82; p < 0.05) and ejection fraction (EF) from ventriculography ( r = 0.86, p < 0.05 vs r = 0.88, p < 0.05 for 2DE SQ compared with EF). MR evaluation of segmental wall motion was relatively stronger in the LAD distribution (MR SQ compared with 2DE SQ: r = 0.86, p < 0.05; MR SQ compared with EF: r = 0.96, p < 0.05) than in the RCA distribution ( r = 0.06, p ≥ 0.05 and r = 0.62, p ≥ 0.05, respectively). For 2DE, regional variations were not as evident (2DE SQ compared with EF: r = 0.90, p < 0.05 for LAD and r = 0.81, p < 0.05 for RCA). For segmental evaluation of wall motion after myocardial infarction, MR imaging (transaxial, multiphasic) appears to be comparable to 2DE overall but superior in LAD distribution and inferior in RCA distribution.