Contrasting the potential benefits of early invasive coronary angiography in acute and chronic myocardial injury patterns.

BACKGROUND: In cases of evolving myocardial injury not definitively attributed to coronary ischaemia precipitated by plaque rupture, referral for invasive coronary angiography (ICA) may be influenced by observed troponin profiles. We sought to explore association between early ICA and elevated high-sensitivity troponin T (hs-cTnT) concentrations with and without dynamic changes, to examine if there may be a hs-cTnT threshold associated with benefit from an initial ICA strategy. METHODS: Using published studies (hs-cTnT study n = 1937, RAPID-TnT study n = 3270) and the Fourth Universal Definition of Myocardial Infarction (MI), index presentations of patients with hs-cTnT concentrations 5-14ng/L were classified as 'non-elevated' (NE). Hs-cTnT greater than upper reference limit (14ng/L) were classified as 'elevated hs-cTnT with dynamic change' (encompassing acute myocardial injury, Type 1 MI, and Type 2 MI), or 'non-dynamic hs-cTnT elevation' (chronic myocardial injury). Patients with hs-cTnT <5ng/L and/or eGFR<15mmol/L/1.73m2 were excluded. ICA was performed within 30 days of admission. Primary outcome was defined as composite endpoint of death, MI, or unstable angina at 12 months. RESULTS: Altogether, 3620 patients comprising 837 (23.1%) with non-dynamic hs-cTnT elevations and 332 (9.2%) with dynamic hs-cTnT elevations were included. Primary outcome was significantly higher with dynamic and non-dynamic hs-cTnT elevations (Dynamic: HR: 4.13 95%CI:2.92-5.82; p<0.001 Non-dynamic: HR: 2.39 95% confidence interval [CI]:1.74-3.28, p<0.001). Hs-cTnT thresholds where benefit from initial ICA strategy appeared to emerge was observed at 110ng/L and 50ng/L in dynamic and non-dynamic elevations, respectively. CONCLUSION: Early ICA appears to portend benefit in hs-cTnT elevations with and without dynamic changes, and at lower hs-cTnT threshold in non-dynamic hs-cTnT elevation. Differences compel further investigation.

Twelve-Month Outcomes of Patients With Myocardial Injury not Due to Type-1 Myocardial Infarction.

BACKGROUND: Diagnosis of acute myocardial infarction (AMI) requires a combination of elevated cardiac troponins, and clinical or echocardiographic evidence of coronary ischaemia. Identification of patients with a high likelihood of coronary plaque rupture (Type 1 myocardial infarction [MI]) is crucial as it is these patients for whom coronary intervention has been well-established to provide benefit and reduce subsequent coronary ischemic events. However, high-sensitivity cardiac troponin (hs-cTn) assays have increasingly identified patients with hs-cTn elevations not due to Type 1 MI where recommendations for ongoing care are currently limited. Understanding the profile and clinical outcomes for these patients may inform the development of an emerging evidence-base. METHODS: Using two previously published studies (hs-cTnT study n=1,937, RAPID-TnT study n=3,270) and the Fourth Universal Definition of MI, index presentations of patients to South Australian emergency departments with suspected AMI, defined by high sensitivity cardiac troponin T (hs-cTnT) greater than the upper reference limit (14 ng/L) and without obvious corresponding ischaemia on electrocardiogram (ECG), were classified as either Type 1 MI (T1MI), Type 2 MI (T2MI), acute myocardial injury (AI), or chronic myocardial injury (CI). Patients with non-elevated hs-cTnT (defined as <14 ng/L) were excluded. Outcomes assessed included death, MI, unstable angina, and non-coronary cardiovascular events within 12 months. RESULTS: In total, 1,192 patients comprising 164 (13.8%) T1MI, 173 (14.5%) T2MI/AI, and 855 (71.7%) CI were included. The rate of death or recurrent acute coronary syndrome was greatest in patients with T1MI, but also occurred with moderate frequency in Type 2 MI/AI and CI (T1MI: 32/164 [19.5%]; T2MI/AI: 24/173 [13.1%]; CI:116/885 [13.6%]; p=0.008). Of all the deaths observed, 74% occurred among those with an initial index diagnostic classification of CI. After adjusting for age, gender and baseline comorbidities, the relative hazard ratios for non-coronary cardiovascular readmissions were similar across all groups: Type 2 MI/AI: 1.30 (95% confidence interval 0.99-1.72, p=0.062); CI: 1.10 (95% confidence interval 0.61-2.00, p=0.75). CONCLUSIONS: Non-T1MI accounted for the majority of patients presenting with elevated hs-cTnT without ischaemia on ECG. Patients with T1MI had the highest rates of death or recurrent AMI; however patients with T2MI/AI and CI experienced a substantial rate of non-coronary cardiovascular re-hospitalisations.

A Pilot Study to Examine the Effect of Passive Straight Leg Raise Performed During Cardiopulmonary Resuscitation on Cerebral Perfusion Measured by Noninvasive Cerebral Oximetry.

Passive leg raise (PLR) during cardiopulmonary resuscitation (CPR) is simple and noninvasive maneuver, which can potentially improve patient-related outcomes. Initial CPR guidelines have previously advocated "elevation of the lower extremities to augment artificial circulation during CPR." There is lack of supporting evidence for this recommendation. DESIGN: This was a double cross-over physiologic efficacy randomized study. SETTING AND PATIENTS: Study in 10 subjects with in-hospital cardiac arrest for whom CPR was undertaken. INTERVENTION: Subjects were randomized to receive two cycles of CPR with PLR followed by two cycles of CPR without PLR (Group I) or vice-versa (Group II). Subjects had their foreheads (right and left) fitted with near infrared spectroscopy (NIRS) electrodes (O3 System-Masimo, Masimo corporation Forty Parker, Irvine CA) while undergoing CPR during the study. NIRS readings, a measure of mixed venous, arterial, and capillary blood oxygen saturation, act as a surrogate measure of cerebral blood perfusion during CPR. MEASUREMENT AND MAIN RESULTS: PLR was randomly used "first" in five of them, whereas it was used "second" in the remaining five subjects. In subjects in whom PLR was performed during first two cycles (Group I), NIRS values were initially significantly greater. The performance of PLR during CPR in Group II attenuated the decline in NIRS readings during CPR. CONCLUSIONS: PLR during CPR is feasible and leads to augmentation of cerebral blood flow. Furthermore, the expected decline in cerebral blood flow over time during CPR may be attenuated by this maneuver. The clinical significance of these findings will require further investigations.

Cardiac tamponade and constrictive pericarditis due to Actinomyces meyeri bacterial pericarditis: a case report.

Background: Purulent bacterial pericarditis (PBP) is a highly lethal infection of the pericardial space that arises as a complication of infective illnesses. Purulent bacterial pericarditis remains a diagnostic challenge given its non-specific clinical and investigative features and carries exceedingly high mortality rates due to fulminant sepsis and morbidity including constrictive pericarditis in survivors. We present our management of cardiac tamponade and subsequent constrictive pericarditis due to Actinomyces meyeri PBP. Case summary: A 53-year-old Caucasian male presented with acute New York Heart Association Class IV dyspnoea and chest discomfort, in the context of multiple hospital presentations over the preceding 8 weeks due to presumed recurrent viral pericarditis. On this admission, initial transthoracic echocardiography (TTE) demonstrated a large asymmetric pericardial effusion for which he underwent urgent pericardiocentesis. Serial TTE post-pericardiocentesis, however, demonstrated effusion re-accumulation and effusive-constrictive pericarditis, confirmed on cardiac magnetic resonance imaging. Fluid culture was positive for A. meyeri. He was diagnosed with PBP, but his condition deteriorated despite appropriate intravenous antibiotic therapy, necessitating semi-urgent surgical pericardiectomy. He recovered well and was discharged on Day 10 post-operatively. Discussion: Unlike uncomplicated acute viral or idiopathic pericarditis, PBP portends a very poor prognosis if unrecognized and untreated. Diagnostic challenges persist given its rarity in modern clinical practice; however, PBP should be considered in cases of seemingly recurrent pericarditis. Multi-modal cardiac imaging and careful analysis of pericardial fluid including cultures and lactate dehydrogenase/serum ratios may assist in earlier recognition. In this case, source control and symptom relief were achieved only with combined intravenous antibiotics, surgical evacuation, and pericardiectomy.