Treatment of Acute Myocardial Infarction and Cardiogenic Shock: Outcomes of the RECOVER III Postapproval Study by Society of Cardiovascular Angiography and Interventions Shock Stage.

BACKGROUND: The Society for Cardiovascular Angiography and Interventions proposed a staging system (A-E) to predict prognosis in cardiogenic shock. Herein, we report clinical outcomes of the RECOVER III study for the first time, according to Society for Cardiovascular Angiography and Interventions shock classification. METHODS AND RESULTS: The RECOVER III study is an observational, prospective, multicenter, single-arm, postapproval study of patients with acute myocardial infarction with cardiogenic shock undergoing percutaneous coronary intervention with Impella support. Patients enrolled in the RECOVER III study were assigned a baseline Society for Cardiovascular Angiography and Interventions shock stage. Staging was then repeated within 24 hours after initiation of Impella. Kaplan-Meier survival curve analyses were conducted to assess survival across Society for Cardiovascular Angiography and Interventions shock stages at both time points. At baseline assessment, 16.5%, 11.4%, and 72.2% were classified as stage C, D, and E, respectively. At ≤24-hour assessment, 26.4%, 33.2%, and 40.0% were classified as stage C, D, and E, respectively. Thirty-day survival among patients with stage C, D, and E shock at baseline was 59.7%, 56.5%, and 42.9%, respectively (P=0.003). Survival among patients with stage C, D, and E shock at ≤24 hours was 65.7%, 52.1%, and 29.5%, respectively (P<0.001). After multivariable analysis of impact of shock stage classifications at baseline and ≤24 hours, only stage E classification at ≤24 hours was a significant predictor of mortality (odds ratio, 4.8; P<0.001). CONCLUSIONS: In a real-world cohort of patients with acute myocardial infarction with cardiogenic shock undergoing percutaneous coronary intervention with Impella support, only stage E classification at ≤24 hours was significantly predictive of mortality, suggesting that response to therapy may be more important than clinical severity of shock at presentation.

Diagnostic Performance of Diastolic Hyperemia-Free Ratio Compared With Invasive Fractional Flow Reserve for Evaluation of Coronary Artery Disease.

Hyperemic and nonhyperemic pressure ratios are frequently used to assess the hemodynamic significance of coronary artery disease and to guide the need for myocardial revascularization. However, there are limited data on the diagnostic performance of the diastolic hyperemia-free ratio (DFR). We evaluated the diagnostic performance of the DFR compared with invasive fractional flow reserve (FFR). We performed a prospective, single-center study of 308 patients (343 lesions) who underwent DFR and FFR for evaluation of visually estimated 40% to 90% stenoses. Diagnostic performance of the DFR compared with FFR was evaluated using linear regression, Bland-Altman analysis, and receiver operating characteristic curves. The overall diagnostic accuracy of the DFR was 83%; the accuracy rates were 86%, 40%, and 95% when the DFR was <0.86, 0.88 to 0.90, and >0.93, respectively. The sensitivity, specificity, positive predicative value, and negative predictive value were 60%, 91%, 71%, and 87%, respectively. The Pearson correlation coefficient was 0.75 (p <0.05). The Bland-Altman analysis showed a mean difference of 0.09, and the area under the receiver operating characteristic curve was 0.88 (95% confidence interval 0.84 to 0.92, p <0.05). In conclusion, the DFR has a good diagnostic performance compared with FFR but 17% of the measurements were discordant. The diagnostic accuracy of the DFR was only 40% when the DFR was 0.88 to 0.90, suggesting that FFR may be useful in these arteries.

A Heart Gone Bananas: Allergy-Induced Coronary Vasospasm due to Banana (Kounis Syndrome).

Kounis syndrome encompasses a variety of cardiovascular signs and symptoms associated with mast cell activation in the setting of allergic or hypersensitivity and anaphylactic or anaphylactoid insults. It can manifest as coronary vasospasm, coronary, or in-stent thrombosis, and acute myocardial infarction with plaque rupture. Various medications as well as foods including fish, shellfish, mushroom, kiwi, and rice pudding have been implicated as causal agents. We present what we believe to be the first documented case of Kounis syndrome manifesting as coronary vasospasm as the result of an allergy to banana. This case highlights the importance of considering allergic causes of angina and allergy referral in a patient with known atopy and an otherwise negative cardiovascular workup. It also emphasizes to consider food allergy, especially banana, as a cause of Kounis syndrome.

P2Y12 inhibitor versus aspirin monotherapy for secondary prevention of cardiovascular events: meta-analysis of randomized trials.

Aim: To compare the efficacy and safety of P2Y12 inhibitor or aspirin monotherapy for secondary prevention in patients with atherosclerotic cardiovascular disease (ASCVD). Methods and results: Medline, Embase, and Cochrane Central databases were searched to identify randomized trials comparing monotherapy with a P2Y12 inhibitor versus aspirin for secondary prevention in patients with ASCVD (cardiovascular, cerebrovascular, or peripheral artery disease). The primary outcome was major adverse cardiac events (MACE). Secondary outcomes were myocardial infarction (MI), stroke, all-cause mortality, and major bleeding. A random-effects model was used to calculate risk ratios (RR) and the corresponding 95% confidence interval (CI) and heterogeneity among studies was assessed using the Higgins I2 value. A total of 9 eligible trials (5 with clopidogrel and 4 with ticagrelor) with 61 623 patients were included in our analyses. Monotherapy with P2Y12 inhibitors significantly reduced the risk of MACE by 11% (0.89, 95% CI 0.84-0.95, I2 = 0%) and MI by 19% (0.81, 95% CI 0.71-0.92, I2 = 0%) compared with aspirin monotherapy. There was no significant difference in the risk of stroke (0.85, 95% CI 0.73-1.01), or all-cause mortality (1.01, 95% CI 0.92-1.11). There was also no significant difference in the risk of major bleeding with P2Y12 inhibitor monotherapy compared with aspirin (0.94, 95% CI 0.72-1.22, I2 = 42.6%). Results were consistent irrespective of the P2Y12 inhibitor used. Conclusion: P2Y12 inhibitor monotherapy for secondary prevention is associated with a significant reduction in atherothrombotic events compared with aspirin alone without an increased risk of major bleeding.

A Novel Catheterization Laboratory Radiation Shielding System: Results of Pre-Clinical Testing.

BACKGROUND: This pre-clinical study evaluated the efficacy of a novel shielding system to reduce scatter radiation in the cardiac catheterization laboratory. METHODS: Using a scatter radiation phantom in a standard cardiac catheterization laboratory, a radiation physicist recorded radiation measurements at 20 reference points on the operator side of the table. Measurements were made with fluoroscopy and cine with the C-arm in the posterior-anterior (PA) and 40 degrees left anterior oblique (LAO) orientations. Scatter radiation doses were compared with and without use of the shielding system. RESULTS: Use of the shielding system was associated with >94.2% reduction in scatter radiation across all reference points in the PA and LAO projections with fluoroscopy and cine. With the shielding system, dose reductions at the location of the primary operator ranged from 97.8% to 99.8%. At locations of maximum scatter radiation, use of the shielding system resulted in dose reductions ranging from 97.8% to 99.8% with fluoroscopy and from 97.9% to 99.8% with cine. CONCLUSIONS: In this pre-clinical study, a novel radiation shielding system was observed to dramatically reduce scatter radiation doses. Based on these results, clinical testing is warranted to determine whether the shielding system will enable operators and staff to perform interventional procedures with less radiation exposure that may obviate the need to wear standard lead apparel. INDEXING WORDS: Radiation safety; occupational health; occupational hazard.

Comparative Safety of Bioabsorbable Polymer Everolimus-Eluting, Durable Polymer Everolimus-Eluting, and Durable Polymer Zotarolimus-Eluting Stents in Contemporary Clinical Practice.

[Figure: see text].

Disparate impact of severe aortic and mitral regurgitation on left ventricular dilation.

In asymptomatic severe aortic (AR) and mitral regurgitation (MR), left ventricular (LV) dimension criteria were established to guide timing of valve replacement to prevent irreversible LV dysfunction. Given both lesions are primary LV volume overload ''leaks'', it might be expected that both lesions would induce similar impact on the LV and result in equivalent dimension criteria for intervention. However, the dimension-based intervention criteria for AR versus MR (developed through natural history studies), differ markedly. The pathophysiological foundations for such discordance have neither been fully elucidated nor emphasized. This case-based treatise compares the two regurgitant lesions with respect to: (a) ''total regurgitant circuits''; (b) ''driving pressures'' resulting in LV volume overload from each respective ''leak''; and (c) volume and afterload wall stresses imposed on the LV.Key points The ''total circuits'' of volume overload differ: The AR circuit includes the LV and systemic vasculature, whereas MR includes the LV ejecting into the left atrium/pulmonary veins and systemic circulation. The ''driving pressure'' of regurgitation and afterload are high with AR and low with MR. Differing ''total circuits'' and ''driving pressures'' impose disparate wall stresses upon the LV. Parallel and serial sarcomere replication occurs in AR, while only serial replication occurs in MR. It therefore follows that for regurgitation of similar severities, AR results in greater LV dilation at the point of irreversible myocardial dysfunction compared to MR. These considerations may explain, at least in part, the disparate dimension criteria employed for valve intervention for severe AR vs MR.

One-year outcomes of supersaturated oxygen therapy in acute anterior myocardial infarction: The IC-HOT study.

BACKGROUND: Supersaturated oxygen (SSO2 ) has recently been approved by the U.S. Food and Drug Administration for administration after primary percutaneous coronary intervention (pPCI) in patients with anterior ST-segment elevation myocardial infarction (STEMI) based on its demonstration of infarct size reduction in the IC-HOT study. OBJECTIVES: To describe the 1-year clinical outcomes of intracoronary SSO2 treatment after pPCI in patients with anterior STEMI. METHODS: IC-HOT was a prospective, open-label, single-arm study in which 100 patients without cardiogenic shock undergoing successful pPCI of an occluded left anterior descending coronary artery were treated with a 60-min SSO2 infusion. One-year clinical outcomes were compared with a propensity-matched control group of similar patients with anterior STEMI enrolled in the INFUSE-AMI trial. RESULTS: Baseline and postprocedural characteristics were similar in the two groups except for pre-PCI thrombolysis in myocardial infarction 3 flow, which was less prevalent in patients treated with SSO2 (9.6% vs. 22.9%, p = .02). Treatment with SSO2 was associated with a lower 1-year rate of the composite endpoint of all-cause death or new-onset heart failure (HF) or hospitalization for HF (0.0% vs. 12.3%, p = .001). All-cause mortality, driven by cardiovascular mortality, and new-onset HF or HF hospitalization were each individually lower in SSO2 -treated patients. There were no significant differences between groups in the 1-year rates of reinfarction or clinically driven target vessel revascularization. CONCLUSIONS: Infusion of SSO2 following pPCI in patients with anterior STEMI was associated with improved 1-year clinical outcomes including lower rates of death and new-onset HF or HF hospitalizations.

Impact of COVID-19 pandemic on STEMI care: An expanded analysis from the United States.

OBJECTIVE: To evaluate the impact of COVID-19 pandemic migitation measures on of ST-elevation myocardial infarction (STEMI) care. BACKGROUND: We previously reported a 38% decline in cardiac catheterization activations during the early phase of the COVID-19 pandemic mitigation measures. This study extends our early observations using a larger sample of STEMI programs representative of different US regions with the inclusion of more contemporary data. METHODS: Data from 18 hospitals or healthcare systems in the US from January 2019 to April 2020 were collecting including number activations for STEMI, the number of activations leading to angiography and primary percutaneous coronary intervention (PPCI), and average door to balloon (D2B) times. Two periods, January 2019-February 2020 and March-April 2020, were defined to represent periods before (BC) and after (AC) initiation of pandemic mitigation measures, respectively. A generalized estimating equations approach was used to estimate the change in response variables at AC from BC. RESULTS: Compared to BC, the AC period was characterized by a marked reduction in the number of activations for STEMI (29%, 95% CI:18-38, p < .001), number of activations leading to angiography (34%, 95% CI: 12-50, p = .005) and number of activations leading to PPCI (20%, 95% CI: 11-27, p < .001). A decline in STEMI activations drove the reductions in angiography and PPCI volumes. Relative to BC, the D2B times in the AC period increased on average by 20%, 95%CI (-0.2 to 44, p = .05). CONCLUSIONS: The COVID-19 Pandemic has adversely affected many aspects of STEMI care, including timely access to the cardiac catheterization laboratory for PPCI.

SCAI shock classification in acute myocardial infarction: Insights from the National Cardiogenic Shock Initiative.

OBJECTIVES: We applied the cardiovascular angiography and interventions (SCAI) shock staging system to patients presenting with acute myocardial infarction and cardiogenic shock (AMI-CS) who were enrolled in the National Cardiogenic Shock Initiative (NCSI). BACKGROUND: The SCAI shock staging system provides a framework for evaluation of patients with CS based on clinical and hemodynamic parameters, but has not been validated in patients with AMI-CS managed with a contemporary treatment algorithm that incorporates early use of Impella. METHODS: Consecutive patients enrolled in NCSI were identified, all of whom were managed with invasive hemodynamic guidance and supported with Impella. Patients were retrospectively categorized into appropriate SCAI shock stages, and outcomes were assessed accordingly. RESULTS: A total of 300 patients were included in the analysis; 182 patients (61%) presented in Stage C shock, 25 (8%) in Stage D, and 93 (31%) in Stage E. Survival to hospital discharge was 76, 76, and 58%, respectively (p = .006). Survival was <20% among patients in Stage E at 24 hr, regardless of baseline stage. There was near perfect agreement in shock staging between two independent clinicians at baseline (kappa = 0.975, 95% CI, 0.95-1.00, p < .001) and at 24 hr (kappa = 0.985, 95% CI, 0.77-1.00, p < .001). CONCLUSION: In patients with AMI-CS enrolled in NCSI, SCAI Shock classification was reproducible, and predicted survival when applied at presentation and at 24 hr.

Strategic Deployment of Cardiology Fellows in Training Using the Accreditation Council for Graduate Medical Education Coronavirus Disease 2019 Framework.

Coronavirus disease 2019 is a global pandemic affecting >3 million people in >170 countries, resulting in >200 000 deaths; 35% to 40% of patients and deaths are in the United States. The coronavirus disease 2019 crisis is placing an enormous burden on health care in the United States, including residency and fellowship training programs. The balance between mitigation, training and education, and patient care is the ultimate determinant of the role of cardiology fellows in training during the coronavirus disease 2019 crisis. On March 24, 2020, the Accreditation Council for Graduate Medical Education issued a formal response to the pandemic crisis and described a framework for operation of graduate medical education programs. Guidance for deployment of cardiology fellows in training during the coronavirus disease 2019 crisis is based on the principles of a medical mission, and adherence to preparation, protection, and support of our fellows in training. The purpose of this review is to describe our departmental strategic deployment of cardiology fellows in training using the Accreditation Council for Graduate Medical Education framework for pandemic preparedness.

Institutional Variability in Patient Radiation Doses ≥5 Gy During Percutaneous Coronary Intervention.

OBJECTIVES: The aim of this study was to evaluate institutional variability in high radiation doses during percutaneous coronary intervention (PCI). BACKGROUND: It is unknown whether radiation safety practices are optimally applied across institutions performing PCI. METHODS: Using data from a large statewide registry, PCI discharges between July 1, 2016, and March 31, 2018, with a procedural air kerma (AK) recorded were analyzed. PCI procedures were grouped by the performing hospital, and institutional frequency of procedural AK ≥5 Gy was calculated. Fitted hierarchical Bayesian modeling was performed to identify variables independently associated with an AK ≥5 Gy. The performing hospital was included as a random effect in the hierarchical model. RESULTS: Among 36,201 PCI procedures at 28 hospitals, procedural AK was ≥5 Gy in 1,477 cases (4.1%), ≥10 Gy in 185 (0.5%), and ≥15 Gy in 105 (0.3%). The institutional frequency of procedural AK ≥5 Gy ranged from 0.0% to 10.9%. Bayesian modeling identified body mass index, dyslipidemia, diabetes, prior coronary bypass surgery, use of mechanical circulatory support, and the performing hospital as independent predictors of an AK ≥5 Gy. The median odds ratio for the performing hospital, representing an estimate of the contribution of interhospital variability in determining the odds of having a procedural AK ≥5 Gy, was 3.08 (95% confidence interval: 3.01 to 3.16). CONCLUSIONS: Wide variability exists in the institutional frequency of procedural AK ≥5 Gy during PCI. After accounting for patient characteristics and procedural variables, the performing hospital appears to be a major factor in determining patient radiation dose in contemporary PCI.

2-Year Outcomes After Stenting of Lipid-Rich and Nonrich Coronary Plaques.

BACKGROUND: Autopsy studies suggest that implanting stents in lipid-rich plaque (LRP) may be associated with adverse outcomes. OBJECTIVES: The purpose of this study was to evaluate the association between LRP detected by near-infrared spectroscopy (NIRS) and clinical outcomes in patients with coronary artery disease treated with contemporary drug-eluting stents. METHODS: In this prospective, multicenter registry, NIRS was performed in patients undergoing coronary angiography and possible percutaneous coronary intervention (PCI). Lipid core burden index (LCBI) was calculated as the fraction of pixels with the probability of LRP >0.6 within a region of interest. MaxLCBI4mm was defined as the maximum LCBI within any 4-mm-long segment. Major adverse cardiac events (MACE) included cardiac death, myocardial infarction, definite or probable stent thrombosis, or unplanned revascularization or rehospitalization for progressive angina or unstable angina. Events were subcategorized as culprit (treated) lesion-related, nonculprit (untreated) lesion-related, or indeterminate. RESULTS: Among 1,999 patients who were enrolled in the COLOR (Chemometric Observations of Lipid Core Plaques of Interest in Native Coronary Arteries Registry), PCI was performed in 1,621 patients and MACE occurred in 18.0% of patients, of which 8.3% were culprit lesion-related, 10.7% were nonculprit lesion-related, and 3.1% were indeterminate during 2-year follow-up. Complications from NIRS imaging occurred in 9 patients (0.45%), which resulted in 1 peri-procedural myocardial infarction and 1 emergent coronary bypass. Pre-PCI NIRS imaging was obtained in 1,189 patients, and the 2-year rate of culprit lesion-related MACE was not significantly associated with maxLCBI4mm (hazard ratio of maxLCBI4mm per 100: 1.06; 95% confidence interval: 0.96 to 1.17; p = 0.28) after adjusting clinical and procedural factors. CONCLUSIONS: Following PCI with contemporary drug-eluting stents, stent implantation in NIRS-defined LRPs was not associated with increased periprocedural or late adverse outcomes compared with those without significant lipid.

Clinical Use of CT-Derived Fractional Flow Reserve in the Emergency Department.

OBJECTIVES: This study sought to examine the feasibility, safety, clinical outcomes, and costs associated with computed tomography-derived fractional flow reserve (FFRCT) in acute chest pain (ACP) patients in a coronary computed tomography angiography (CTA)-based triage program. BACKGROUND: FFRCT is useful in determining lesion-specific ischemia in patients with stable ischemic heart disease, but its utility in ACP has not been studied. METHODS: ACP patients with no known coronary artery disease undergoing coronary CTA and coronary CTA with FFRCT were studied. FFRCT ≤0.80 was considered positive for hemodynamically significant stenosis. RESULTS: Among 555 patients, 297 underwent coronary CTA and FFRCT (196 negative, 101 positive), whereas 258 had coronary CTA only. The rejection rate for FFRCT was 1.6%. At 90 days, there was no difference in major adverse cardiac events (including death, nonfatal myocardial infarction, and unexpected revascularization after the index visit) between the coronary CTA and FFRCT groups (4.3% vs. 2.7%; p = 0.310). Diagnostic failure, defined as discordance between the coronary CTA or FFRCT results with invasive findings, did not differ between the groups (1.9% vs. 1.68%; p = NS). No deaths or myocardial infarction occurred with negative FFRCT when revascularization was deferred. Negative FFRCT was associated with higher nonobstructive disease on invasive coronary angiography (56.5%) than positive FFRCT (8.0%) and coronary CTA (22.9%) (p < 0.001). There was no difference in overall costs between the coronary CTA and FFRCT groups ($8,582 vs. $8,048; p = 0.550). CONCLUSIONS: In ACP, FFRCT is feasible, with no difference in major adverse cardiac events and costs compared with coronary CTA alone. Deferral of revascularization is safe with negative FFRCT, which is associated with higher nonobstructive disease on invasive angiography.

Relationship Between Troponin on Presentation and In-Hospital Mortality in Patients With ST-Segment-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention.

Background Troponin release in ST-segment-elevation myocardial infarction (STEMI) has predictable kinetics with early levels reflective of ischemia duration. Little research has examined the value of admission troponin levels in STEMI patients undergoing primary percutaneous coronary intervention. We investigated the relationship between troponin on presentation and mortality in a large, real-world cohort of STEMI patients undergoing primary percutaneous coronary intervention. Methods and Results We used multivariable adaptive regression modeling to examine the association between admission troponin levels and in-hospital mortality for patients who underwent primary percutaneous coronary intervention for STEMI. We adjusted for known clinical risk factors using a validated mortality risk model derived from the NCDR (National Cardiovascular Data Registry) CathPCI database, and this same model was used to calculate patients' predicted mortality based on clinical and demographic factors. Patients were then stratified by troponin groups to compare predicted versus observed mortality. Of the 14 061 patients included in the cohort, 47.2% had initial troponin levels that were undetectable or within the reference range. Admission troponin was an independent predictor of in-hospital mortality, and any value above the reference range was associated with increased mortality (1.8% versus 5.1%, [standardized difference, 18.2%]). Patients with the highest predicted risk for mortality (13% predicted) in the highest admission troponin grouping experienced an observed mortality of 19.5%. Patients in low troponin groupings consistently demonstrated lower than predicted mortality based on their clinical and demographic risk profile. Conclusions Nearly half of patients undergoing primary percutaneous coronary intervention had normal troponin on presentation and had a relatively good outcome. Mortality increases with elevated admission troponin levels, regardless of baseline clinical risk. The substantial number of patients who present with markedly elevated troponin and their relatively worse outcomes highlights the need for continued improvement in prehospital STEMI detection and care.

Disparate Impact of Ischemic Injury on Regional Wall Dysfunction in Acute Anterior vs Inferior Myocardial Infarction.

BACKGROUND: Acute transmural ischemia should induce similar magnitude of wall motion abnormality (WMA) in both anterior myocardial infarction (AMI) and inferior (IMI). However, patients with AMI generally suffer more severe hemodynamic compromise. METHODS: This retrospective study compared WMA's in ST segment elevation MI patients undergoing primary reperfusion and subsequent cardiac MRI. Regional systolic wall motion and thickening were assessed in all segments throughout the left ventricle (LV). RESULTS: We analyzed 37 patients (AMI = 24 vs IMI = 13). Reperfusion success was achieved in all and there were no differences between groups in door-to-balloon time (AMI median 77 vs IMI 119 min, p = 0.085). Compared to IMI, in AMI LV ejection fraction was more depressed (37 ±â€¯7.6% vs 51 ±â€¯10.3%, P = 0.0006) and regional WMA more severe (total regional WMA score = 2.63 ±â€¯0.53 vs IMI = 2.1 ±â€¯0.52, P = 0.007). Regional dyskinesis was commonly observed in AMI patients but was rare in IMI (79% vs 7% of cases). Similarly, AMI manifested systolic thinning, whereas thickening was depressed but still present in IMI patients. Strikingly, WMA severity differed downstream relative to the origin of the infarct artery: In all AMI cases, WMA worsened from proximal anterior toward the distal apical zone; in IMI the pattern was reverse, with WMA consistently most severe in the basal segment of the inferior-posterior wall with preservation toward the apical distribution of the infarct vessel. CONCLUSION: These results demonstrate a disparate impact of ischemic injury on mechanical performance of the anterior vs inferior-posterior walls. These findings may be attributable to differences between the walls in architecture, mechanics and coronary blood flow. These observations may have implications for myocardial salvage, remodeling and prognosis.

Contemporary use of and outcomes associated with ultra-low contrast volume in patients undergoing percutaneous coronary interventions.

BACKGROUND: The risk of contrast-induced acute kidney injury (CI-AKI) increases in a nonlinear fashion with increasing volume of contrast media. Prior studies recommend limiting contrast volume to less than three times the estimated creatinine clearance (CC). Recently, a number of operators have reported successful percutaneous coronary intervention (PCI) using even lower volumes of contrast. OBJECTIVES: To evaluate the prevalence and outcomes associated with ultra-low contrast volume among patients undergoing PCI. METHODS: We assessed the prevalence and outcomes associated with use of ultra-low contrast volume among 75 393 patients undergoing PCI in Michigan between July 2014 and June 2017 in the BMC2 (Blue Cross Blue Shield of Michigan Cardiovascular Consortium) registry. Ultra-low contrast volume was defined as contrast volume less than or equal to the patient's estimated CC. Patients receiving dialysis at the time of the procedure were excluded. RESULTS: Ultra-low contrast volume was used in 13% of procedures with the majority of these patients being at low risk of renal complications. Compared with patients who received a contrast volume between one and three times the CC, use of ultra-low volume of contrast was associated with a significantly lower incidence of AKI (aOR 0.682, 95% CI 0.566-0.821, P < 0.001) and a lower incidence of need for dialysis (aOR = 0.341, 95% CI 0.165-0.704, P = 0.003). These benefits were most evident in the patients with a high baseline predicted risk of AKI. CONCLUSIONS: A small but clinically significant number of patients are treated with ultra-low contrast volume. Ultra-low contrast volume use is associated with a significant reduction in the incidence of AKI or need for dialysis. It may be prudent to consider this new threshold when performing PCI on patients who are at an increased risk of AKI.