Association between vessel-specific coronary Aggregated plaque burden, Agatston score and hemodynamic significance of coronary disease (The CAPTivAte study)

Background

CT coronary angiography (CTCA) is a guideline-endorsed assessment for patients with stable angina and suspected coronary disease. Although associated with excellent negative predictive value in ruling out obstructive coronary disease, there are limitations in the ability of CTCA to predict hemodynamically significant coronary disease. The CAPTivAte study aims to assess the utility of Aggregated Plaque Burden (APB) in predicting ischemia based on Fractional Flow Reserve (FFR).

Methods

In this retrospective study, patients who had a CTCA and invasive FFR of the LAD were included. The entire length of the LAD was analyzed using semi-automated software which characterized total plaque burden and plaque morphological subtype (including Low Attenuation Plaque (LAP), Non-calcific plaque (NCP) and Calcific Plaque (CP). Aggregated Plaque Burden (APB) was calculated. Univariate and multivariate analysis were performed to assess the association between these CT-derived parameters and invasive FFR.

Results

There were 145 patients included in this study. 84.8 % of patients were referred with stable angina. There was a significant linear association between APB and FFR in both univariate and multivariate analysis (Adjusted R-squared = 0.0469; p = 0.035). Mean Agatston scores are higher in FFR positive vessels compared to FFR negative vessels (371.6 (±443.8) vs 251.9 (±283.5, p = 0.0493).

Conclusion

CTCA-derived APB is a reliable predictor of ischemia assessed using invasive FFR and may aid clinicians in rationalizing invasive vs non-invasive management strategies. Vessel-specific Agatston scores are significantly higher in FFR-positive vessels than in FFR-negative vessels. Associations between HU-derived plaque subtype and invasive FFR were inconclusive in this study.

The ability of contemporary cardiologists to judge the ischemic impact of a coronary lesion visually

BACKGROUND

Landmark trials showed that invasive pressure measurement (Fractional Flow Reserve, FFR) was a better guide to coronary stenting than visual assessment. However, present-day interventionists have benefited from extensive research and personal experience of mapping anatomy to hemodynamics.

AIMS

To determine if visual assessment of the angiogram performs as well as invasive measurement of coronary physiology.

METHODS

25 interventional cardiologists independently visually assessed the single vessel coronary disease of 200 randomized participants in The Objective Randomized Blinded Investigation with optimal medical Therapy of Angioplasty in stable angina trial (ORBITA). They gave a visual prediction of the FFR and Instantaneous Wave-free Ratio (iFR), denoted vFFR and viFR respectively. Each judged each lesion on 2 occasions, so that every lesion had 50 vFFR, and 50 viFR assessments. The group consensus visual estimates (vFFR-group and viFR-group) and individual cardiologists' visual estimates (vFFR-individual and viFR-individual) were tested alongside invasively measured FFR and iFR for their ability to predict the placebo-controlled reduction in stress echo ischemia with stenting.

RESULTS

Placebo-controlled ischemia improvement with stenting was predicted by vFFR-group (p < 0.0001) and viFR-group (p < 0.0001), vFFR-individual (p < 0.0001) and viFR-individual (p < 0.0001). There were no significant differences between the predictive performance of the group visual estimates and their invasive counterparts: p = 0.53 for vFFR vs FFR and p = 0.56 for viFR vs iFR.

CONCLUSION

Visual assessment of the angiogram by contemporary experts, provides significant additional information on the amount of ischaemia which can be relieved by placebo-controlled stenting in single vessel coronary artery disease.

Immediate recruitment of dormant coronary collaterals can provide more than half of normal resting perfusion during coronary occlusion in patients with coronary artery disease

BACKGROUND

Dormant coronary collaterals are highly prevalent and clinically beneficial in cases of coronary occlusion. However, the magnitude of myocardial perfusion provided by immediate coronary collateral recruitment during acute occlusion is unknown. We aimed to quantify collateral myocardial perfusion during balloon occlusion in patients with coronary artery disease (CAD).

METHODS

Patients without angiographically visible collaterals undergoing elective percutaneous transluminal coronary angioplasty (PTCA) to a single epicardial vessel underwent two scans with 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT). All subjects underwent at least three minutes of angiographically verified complete balloon occlusion, at which time an intravenous injection of the radiotracer was administered, followed by SPECT imaging. A second radiotracer injection followed by SPECT imaging was performed 24 h after PTCA.

RESULTS

The study included 22 patients (median [interquartile range] age 68 [54-72] years. The perfusion defect extent was 19 [11-38] % of the LV, and the collateral perfusion at rest was 64 [58-67]% of normal.

CONCLUSION

This is the first study to describe the magnitude of short-term changes in coronary microvascular collateral perfusion in patients with CAD. On average, despite coronary occlusion and an absence of angiographically visible collateral vessels, collaterals provided more than half of the normal perfusion.

Vessel-Specific Outcomes of Deferred Revascularization Following Negative Fractional Flow Reserve

Variations in myocardial supply area and hydrostatic pressure gradients result in greater likelihood of positive fractional flow reserve (FFR) in the left anterior descending (LAD) compared with the circumflex (Cx) and right coronary artery (RCA). However, the same FFR threshold for deferral of revascularization is applied to all arteries, without evidence that this results in equivalent outcomes. We assessed vessel-specific outcomes of deferred revascularization for the 3 major coronary arteries based on FFR > 0.8. In this retrospective study, data were obtained on consecutive patients who underwent indicated FFR assessment across 2 tertiary institutions. Patients with deferred revascularization were followed for 36 months for the primary end point of vessel-specific target lesion failure (TLF). Of 1,916 major coronary arteries (1,579 patients), the odds ratio of positive FFR was highest in the LAD (odds ratio 3.36, p <0.001). In total, 867 vessels (733 patients) with FFR > 0.8 had complete 3-year medical record follow-ups. The TLF rate for deferred vessels was 10.21%, 11.52%, and 10.96% for the LAD, Cx, and RCA respectively. In a multivariate analysis, there was no significant difference in the odds of TLF for the 0.84 (0.53 to 1.33, p = 0.459), 1.17 (0.68 to 2.01, p = 0.582), and 1.11 (0.62 to 2.00, p = 0.715) in the LAD, Cx, and RCA, respectively. In a multivariate analysis, diabetes mellitus was the only baseline characteristic significantly associated at risk of TLF (1.43 [1.01 to 2.02], p = 0.043). In conclusion, despite greater likelihood of positive FFR in the LAD, the FFR threshold for deferred revascularization resulted in equivalent outcomes in all 3 major coronary arteries, and patients with diabetes mellitus may represent a group that requires aggressive surveillance and risk factor modification after deferred revascularization.

Impact of coronary disease patterns, anatomical factors, micro-vascular disease and non-coronary cardiac factors on invasive coronary physiology

Invasive coronary physiology has been applied by interventional cardiologists to guide the management of coronary artery disease (CAD), with well-defined thresholds applied to determine whether CAD should be managed with optimal medical therapy (OMT) alone or OMT and percutaneous coronary intervention (PCI). There are multiple modalities in clinical use, including hyperaemic and non-hyperaemic indices. Despite endorsement in the major guidelines, there are various factors which impact and confound the readings of invasive coronary physiology, both within the coronary tree and beyond. This review article aims to summarise the mechanisms by which these factors impact invasive coronary physiology, and distinguish factors that contribute to ischaemia from confounding factors. The potential for mis-classification of ischaemic status is highlighted. Lastly, the authors identify targets for future research to improve the precision of physiology-guided management of CAD.

Outcomes of deferred revascularisation following negative fractional flow reserve in diabetic and non-diabetic patients: a meta-analysis

BACKGROUND

Fractional Flow Reserve (FFR) is a widely applied invasive physiological assessment, endorsed by major guidelines to aid in the decision to perform or defer revascularisation. While a threshold of  > 0.8 has been applied universally, clinical outcomes may be affected by numerous factors, including the presence of diabetes. This meta-analysis aims to investigate the outcomes of diabetic versus non-diabetic patients in whom revascularisation was deferred based on negative FFR.

METHODS

We performed a meta-analysis investigating the outcomes of diabetic and non-diabetic patients in whom revascularisation was deferred based on negative FFR. A search was performed on MEDLINE, PubMed and EMBASE, and peer-reviewed studies that reported MACE for diabetic and non-diabetic patients with deferred revascularisation based on FFR  > 0.8 were included. The primary end point was MACE.

RESULTS

The meta-analysis included 7 studies in which 4275 patients had revascularisation deferred based on FFR > 0.8 (1250 diabetic). Follow up occurred over a mean of 3.2 years. Diabetes was associated with a higher odds of MACE (OR = 1.66, 95% CI 1.35-2.04, p =  < 0.001), unplanned revascularisation (OR = 1.48, 95% CI 1.06-2.06, p = 0.02), all-cause mortality (OR = 1.74, 95% CI 1.20-2.52, p = 0.004) and cardiovascular mortality (OR = 2.08, 95% CI 1.07-4.05, p = 0.03).

CONCLUSIONS

For patients with stable coronary syndromes and deferred revascularisation based on FFR > 0.8, the presence of diabetes portends an increased long-term risk of MACE compared to non-diabetic patients. Trail registration URL:  https://www.crd.york.ac.uk/PROSPERO/ ; Unique identifier: CRD42022367312.

Safety and Feasibility of Rotational Atherectomy in Severe Aortic Stenosis

OBJECTIVES

We aimed to evaluate the safety and feasibility of rotational atherectomy (RA) in patients with severe aortic stenosis (AS).

BACKGROUND

Heavily calcified coronary lesions are commonly encountered in elderly patients with severe AS who are being considered for transcatheter aortic valve implantation. The use of RA in these patients is controversial as they may be at a higher risk of complications.

METHODS

We retrospectively enrolled patients with severe AS who underwent RA across two hospitals from March 2010 to September 2019. Patients with severe AS prior to or within 8 weeks of RA were included.

RESULTS

Twenty-seven (27) consecutive patients (83±5.2 yrs 63% male) with severe AS (peak velocity 4.1±0.5 m/s, mean gradient 40.0±10.2 mmHg) were enrolled and 31 lesions were treated with RA across 30 separate procedures. Three (3) (11.1%) patients had left ventricular ejection fraction ≤30%. Nine (9) (30%) procedures involved percutaneous coronary intervention of multiple arteries, with most lesions in the right coronary artery (51.6%) and left anterior descending artery (32.3%). Three (3) (9.7%) lesions were in the left main stem. RA-facilitated stenting was successful in all lesions. There were no episodes of coronary perforation or slow-flow/no-reflow. There was one episode of coronary dissection in an artery that did not undergo RA, which was successfully treated with a drug-eluting stent. There were no deaths within 30 days and three deaths (11.1%) within 1 year.

CONCLUSIONS

Rotational atherectomy in patients with severe AS is feasible and has a low rate of procedural complications.

Angiographic predictors of coronary hemodynamics

Aims: Assess the correlation between diameter stenosis, lesion length, location, diffuse coronary disease and with fractional flow reserve (FFR). Methods/Results: We performed quantitative coronary analysis analysis on 384 lesions with stable coronary artery disease undergoing FFR assessment. Vessels were 59.1% left anterior descending artery (LAD), 16.1% left circumflex artery and 14.8% right coronary artery. Median diameter stenosis was 58% ± 2.5 and median lesion length was 10 mm ± 7.36. 21% of vessels were diffusely diseased. Lesions were 33.6% proximal, 44% mid-vessel and 12% distal. Median FFR was 0.85. Diameter stenosis correlated with lower FFR (p < 0.005, odds ratio [OR]: 2.4 [95% CI: 0.99-5.63]). There was no association between lesion length, location, number of proximal side branches and FFR. Vessels with diffuse disease had a nonsignificant trend for lower FFR (0.84 vs 0.85, p = 0.375, OR: 1.26 [95% CI: 0.76-2.09]). LAD lesions had significantly lower FFR compared with non-LAD (p < 0.001, OR: 2.55 [95% CI: 1.61-4.04]); including left circumflex artery and right coronary artery lesions (p = 0.001, OR: 3.4 [95% CI: 1.7-6.9]) and p = 0.02, OR: 2.55 [95% CI: 1.17-4.34]). Conclusion: FFR is not related to lesion length, location or number of proximal branches.

Coronary collaterals provide more than half of normal perfusion in patients with coronary artery disease - quantification by myocardial perfusion SPECT during elective balloon occlusion

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

The coronary collateral circulation is a preformed network of anastomotic connections acting as a "natural bypass" mechanism. Whilst the prevalence of collaterals varies between species, approximately 25% of patients have angiographically visible robust collaterals at the time of ST elevation myocardial infarction. While the presence of collaterals is associated with improved outcomes, the magnitude of myocardial perfusion which can be provided by the collateral circulation remains uncertain.

PURPOSE

The aim was to quantify collateral myocardial perfusion during experimental coronary balloon occlusion in patients with CAD.

METHODS

The study was approved by the local investigational review board, and all patients provided informed consent. Patients without prior infarction, bypass surgery, or angiographically visible collaterals undergoing elective percutaneous transluminal coronary angioplasty (PTCA) to a single epicardial vessel, underwent two scans with 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT). All subjects underwent at least three minutes of angiographically verified complete balloon occlusion, at which time an intravenous injection of the radiotracer was administered, followed by SPECT imaging. A second radiotracer injection followed by SPECT imaging was performed 24 hours after PTCA.

RESULTS

The study included 21 patients (median [interquartile range] age 70 [56-74] years, 52% male). The degree of diameter stenosis of treated vessels ranged from 60-99%, with successful PTCA performed with a mean 5-minute balloon occlusion time, resulting in ≤20% residual stenosis in all cases. The vessels undergoing PTCA were 6 in the LAD, 5 in the LCx, and 10 in the RCA. For the cohort, the size of the perfusion defect was 16 [8-30]% of the LV and the collateral perfusion at rest within the perfusion defect was 64 [58-68]% of normal perfusion within that region. Collateral perfusion was negatively correlated with perfusion defect size (R2 = 0.85, p &lt; 0.001), but did not differ by sex (p = 0.27) or age (p = 0.58). CONCLUSIONS: This is the first study to describe the magnitude of microvascular collateral perfusion in CAD. On average, despite coronary occlusion and an absence of angiographically visible collateral vessels, collaterals provide approximately 60% of the perfusion that reaches the jeopardized myocardium during coronary occlusion. This magnitude of collateral perfusion is much higher than previously speculated. A previous study using microspheres in dogs found that collateral perfusion in the setting of an occluded vessel was 6% of normal. By comparison, the current study found ten times greater collateral perfusion in patients with CAD.

Abstract Figure. Collateral perfusion during occlusion.

Amiodarone in the aged

Amiodarone is a highly effective antiarrhythmic drug, but can have serious adverse effects, particularly in older patients. If possible it should not be used purely for controlling the heart rate

If a prescription for amiodarone is contemplated, particularly for an older patient, consult a cardiologist. Avoid amiodarone in patients with significant conduction system disease, significant liver or pulmonary disease, or hyperthyroidism

Regular monitoring of the patient, clinically and biochemically, is required to identify complications at an early, treatable stage. Maintain a high level of suspicion if a patient taking amiodarone is experiencing adverse reactions and presents with new symptoms

Consider potential drug interactions when other drugs are prescribed with amiodarone. The effects and toxicities of amiodarone may persist weeks after it is stopped

Contemporary Management of ST-Elevation Myocardial Infarction

Recent advances have caused a major shift in the way ST-elevation myocardial infarctions are managed. This review explores the pharmacological and interventional techniques that have evidence for improving outcomes and the landmark trials that have sparked change. The new P2Y₁₂ inhibitors, ticagrelor and prasugrel, have been shown to be superior to clopidogrel in STEMI patients undergoing primary percutaneous coronary intervention. Concurrently, many technical aspects of percutaneous coronary intervention have been further clarified by trial data, with bare-metal stents, routine thrombus aspiration and femoral access showing evidence of inferiority. Ongoing trials will provide more information on the role of non-culprit lesion PCI, bioresorbable vascular scaffolds, mechanical devices in persistent ischaemia and early automatic implantable cardioverter-defibrillators for inducible ventricular tachycardia.