Questing for Circadian Dependence in ST-Segment–Elevation Acute Myocardial Infarction

Daytime variation of in-hospital mortality and low cardiac output syndrome after pediatric cardiac surgery-a retrospective cohort study

OBJECTIVE

Recent studies suggest that adult cardiac surgery performed in the morning increases the risk of major adverse cardiac events, but it is unclear whether this association exists in pediatric cardiac surgery. This study aimed to determine whether the composite outcome of in-hospital mortality and low cardiac output syndrome (LCOS) differs between morning and afternoon pediatric cardiac surgeries.

METHODS

This retrospective cohort study enrolled 23,433 consecutive pediatric patients who underwent cardiac surgery between August 2014 and December 2021. Pediatric patients who had surgery start time between 8 AM and 11 AM (morning surgery) versus between 2 PM and 5 PM (afternoon surgery) were compared in the risk of the composite outcome. The Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery (STAT) score was used to indicate the surgical complexity. The adjusted odds radio (aOR) for the composite outcome was calculated using multivariate logistic regression. The restricted cubic spline (RCS) was performed to characterize the continuous relationship between the surgery start time and risk of the composite outcome.

RESULTS

Of 16,534 included pediatric patients, 1.2% died after morning surgery and 0.6% died after afternoon surgery. The composite outcome of in-hospital mortality and LCOS occurred in 14.2% (1,507 of 10,591) of morning surgeries and 8.6% (514 of 5,943) of afternoon surgeries: morning versus afternoon aOR, 1.186 (95% CI, 1.046 to 1.344; p = 0.008). The association was also determined in children aged 3 to 18 years (aOR = 1.598, p = 0.003), weighted between 6.1 to 8.7 kg (aOR = 1.453, p = 0.006), or more than 13 kg (aOR = 1.488, p = 0.019), and with STAT category 4-5 (aOR = 1.367, p = 0.014) subgroups. The RCS plot showed that the aOR of the composite outcome decreased with a delay in the start time of surgery.

CONCLUSION

Our study supports the selective afternoon scheduling of specific pediatric cardiac surgeries, but further investigation is needed in a multicenter cohort.KEY MESSAGESThis study reviewed 23,433 consecutive pediatric patients who underwent cardiac surgery between August 2014 and December 2021.This study suggested that afternoon surgery was associated with a lower risk of the composite outcomes of in-hospital mortality and low cardiac output syndrome.The above association was also determined in children aged 3 to 18 years, weighted between 6.1 and 8.7 kg, or more than 13 kg, and with STAT category 4-5 subgroups.The restricted cubic spline plot showed that the adjusted risk of the composite outcome decreased with a delay in the start time of surgery.Our findings support selective afternoon scheduling for specific pediatric cardiac surgery.

Time-of-Day and Clinical Outcomes After Surgical or Transcatheter Aortic Valve Replacement: Insights From the PARTNER Trials

BACKGROUND

Circadian rhythms may influence myocardial tolerance to ischemia-reperfusion phenomena occurring during cardiac procedures. While conflicting results exist on the effect of time-of-day on surgical aortic valve replacement (SAVR), afternoon procedures could be associated with a reduced risk of death, rehospitalization or periprocedural myocardial infarction, compared with morning procedures. We examined the impact of procedure time-of-day on outcomes after transcatheter aortic valve replacement (TAVR) or SAVR.

METHODS

We analyzed patients at intermediate- or high-surgical risk who underwent elective TAVR (n=4457) or SAVR (n=1129) in the PARTNER (Placement of Aortic Transcatheter Valve) 1 and 2 trials and registries according to time-of-day (morning versus afternoon) using the Kaplan-Meier event rates and multivariable Cox proportional hazards regression models. Sensitivity analysis was conducted using 1:1 propensity-score matching. The primary end point was all-cause death or rehospitalization at 2 years.

RESULTS

At 2 years, no difference was observed between patients operated in the morning versus the afternoon within the SAVR (32.3% versus 30.6%, adjusted hazard ratio, 1.08 [95% CI, 0.82-1.41], P=0.58) and TAVR cohorts (35.7% versus 35.4%, adjusted hazard ratio, 1.01 [95% CI, 0.89-1.14], P=0.86) with regards to the primary end point. Rates of periprocedural myocardial infarction were low and similar between morning and afternoon in SAVR (1.6% versus 1.0%, P=0.51) and TAVR (0.4% versus 0.4%, P=0.86), as were all other clinical end points. Similar results were observed in propensity-score matched analysis.

CONCLUSIONS

Procedure time-of-day was not associated with clinical outcomes after TAVR or SAVR. Registration: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT00530894, NCT01314313, NCT03222141, and NCT03222128.

The Vascular Circadian Clock in Chronic Kidney Disease

Chronic kidney disease is associated with extremely high cardiovascular mortality. The circadian rhythms (CR) have an impact on vascular function. The disruption of CR causes serious health problems and contributes to the development of cardiovascular diseases. Uremia may affect the master pacemaker of CR in the hypothalamus. A molecular circadian clock is also expressed in peripheral tissues, including the vasculature, where it regulates the different aspects of both vascular physiology and pathophysiology. Here, we address the impact of CKD on the intrinsic circadian clock in the vasculature. The expression of the core circadian clock genes in the aorta is disrupted in CKD. We propose a novel concept of the disruption of the circadian clock system in the vasculature of importance for the pathology of the uremic vasculopathy.

Association between In-hospital Mortality and Low Cardiac Output Syndrome with Morning versus Afternoon Cardiac Surgery

BACKGROUND

Recent work suggests that having aortic valve surgery in the morning increases risk for cardiac-related complications. This study therefore explored whether mortality and cardiac complications, specifically low cardiac output syndrome, differ for morning and afternoon cardiac surgeries.

METHODS

The study included adults who had aortic and/or mitral valve repair/replacement and/or coronary artery bypass grafting from 2011 to 2018. The components of the in-hospital composite outcome were in-hospital mortality and low cardiac output syndrome, defined by requirement for at least two inotropic agents at 24 to 48 h postoperatively or need for mechanical circulatory support. Patients who had aortic cross-clamping between 8 and 11 am (morning surgery) versus between 2 and 5 pm (afternoon surgery) were compared on the incidence of the composite outcome.

RESULTS

Among 9,734 qualifying operations, 0.4% (29 of 6,859) died after morning, and 0.7% (20 of 2,875) died after afternoon surgery. The composite of in-hospital mortality and low cardiac output syndrome occurred in 2.8% (195 of 6,859) of morning patients and 3.4% (97 of 2,875) of afternoon patients: morning versus afternoon confounder-adjusted odds ratio, 0.96 (95% CI, 0.75 to 1.24; P = 0.770). There was no evidence of interaction between morning versus afternoon and surgery type (P = 0.965), and operation time was statistically nonsignificant for surgery subgroups.

CONCLUSIONS

Patients having aortic valve surgery, mitral valve surgery, and/or coronary artery bypass grafting with aortic cross-clamping in the morning and afternoon did not have significantly different outcomes. No evidence was found to suggest that morning or afternoon surgical timing alters postoperative risk.

EDITOR’S PERSPECTIVE

Revisiting the Biological Variability of Cardiac Troponin: Implications for Clinical Practice

The diagnosis of acute myocardial injury requires a rise and/or fall of cardiac troponin (cTn) on serial testing, with at least one concentration above the 99th percentile value of a normal reference population according to the recently published Fourth Universal Definition of Myocardial Infarction.1 However, the magnitude of change in cTn that constitutes a significant rise and/or fall was again not specified in detail. High-sensitivity cardiac troponin (hs-cTn) assays can measure ten-fold lower concentrations of cTn with more precision than older assays, and can accurately quantify cTn in more than 50% of healthy individuals with a coefficient of variation of less than 10% at the 99th percentile. These hs-cTn assays are also able to detect the normal variations in cTn results that are due to biological variability. Understanding and quantifying the normal variations in cTn is important as this would allow significant changes to be better defined. Numerous studies have sought to investigate the biological variability of cTn over the last ten years. Such studies are usually conducted in healthy individuals, however individuals with chronic cardiac disease or chronic renal failure have also been examined. These studies have yielded varying results in regards to significant change values for cTn. In light of the recent redefinition for myocardial infarction, the purpose of this mini-review is to revisit the biological variability of cTn. In particular, we outline concepts for determining a significant change value, review the results of previous studies on the biological variation of cTn and discuss potential considerations for clinical practice.

Time-of-day at symptom onset was not associated with infarct size and long-term prognosis in patients with ST-segment elevation myocardial infarction

Background

ST-segment elevation myocardial infarction (STEMI) displays circadian variability with the highest incidence in the morning hours. Data on whether the time-of-day at symptom onset affects infarct size or patients’ long-term prognosis are conflicting. We sought to investigate the association of time-of-day at symptom onset with infarct size or long-term mortality in patients with STEMI undergoing primary percutaneous coronary intervention (PPCI).

Methods

This study included 1206 STEMI patients undergoing PPCI. All patients underwent single photon emission computed tomography (SPECT) imaging with 99mTc-sestamibi before and 7–14 days after PPCI. The co-primary endpoints were final infarct size on day 10 after STEMI and all-cause mortality at 5-year follow-up. Time-of-day at symptom onset of STEMI was categorized in 6-h intervals.

Results

In patients presenting from 0 to 6 h, 6 to 12 h, 12 to 18 h, and 18 to 24 h, the infarct sizes (median [25th–75th percentiles]) were 10.0 [3.0–24.7], 10.0 [3.0–24.0], 10.0 [3.0–22.0], and 9.0 [3.0–21.0] of the left ventricle, respectively (p = 0.87); the Kaplan–Meier estimates of 5-year all-cause mortality were 13.6%, 8.7%, 13.7% and 9.3%, respectively (log-rank test p = 0.30). After adjustment, time-of-day was not associated with infarct size (p ≥ 0.76 for comparisons with infarct size from reference [6–12 h] time interval) or 5-year all-cause mortality (p ≥ 0.25 for comparisons with mortality from reference [6–12 h] time interval). Time-of-day at symptom onset of STEMI was not associated with differences in the recovery of left ventricular ejection fraction 6 months after STEMI.

Conclusions

In patients with STEMI undergoing PPCI, time-of-day at symptom onset was neither associated with scintigraphic infarct size, left ventricular ejection fraction recovery at 6 months nor with 5-year mortality.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1934-z) contains supplementary material, which is available to authorized users.

Cardiovascular daytime varying effect in cardiac surgery on surgical site infections and 1-year mortality: A prospective cohort study with 22,305 patients

Afternoon aortic valve replacement surgery may provide perioperative myocardial protection and improve patient outcomes compared with morning surgery. The results of our large observational study based on Swiss cardiac surgical site infection surveillance data suggest that the current evidence is insufficient to generally promote afternoon cardiac surgeries.

Circadian Rhythm and ST-Segment Elevation Myocardial Infarction: Insights From the Third Gulf Registry of Acute Coronary Events (Gulf RACE-3Ps)

Circadian rhythms have been identified in multiple physiological processes that may affect cardiovascular diseases, yet little is known about the impact of circadian rhythm on acute ST-segment elevation myocardial infarction (STEMI) onset and outcomes in the Middle East. The relationship between time of symptom onset during the 24-hour circadian cycle and prehospital delays and in-hospital death was assessed in 2909 patients with STEMI presenting in 6 Arabian Gulf countries. A sinusoidal smoothing function was used to show the average circadian trends. There was a significant association between time of symptom onset and the circadian cycle. The STEMIs were more frequent during the late morning and early afternoon hours ( P < .001). Patients with pain onset from 0.00 to 5:59 had median prehospital delays of 150 minutes versus 90 minutes from 6:00 to 11:59 and 12:00 to 17:59, respectively ( P < .001). Although there was no significant difference in mortality between the 4 groups ( P = .230), there was a significant association between time of symptom onset as sinusoidal function and in-hospital mortality ( P = .032). Patients with STEMI in the Middle East have significant circadian patterns in symptoms onset, prehospital delay, and timeliness of reperfusion. A circadian rhythm of in-hospital mortality was found over the 24-hour clock of symptom onset time.

Vasculature on the clock: Circadian rhythm and vascular dysfunction

The master mammalian circadian clock (i.e. central clock), located in the suprachiasmatic nucleus of the hypothalamus, orchestrates the synchronization of the daily behavioural and physiological rhythms to better adapt the organism to the external environment in an anticipatory manner. This central clock is entrained by a variety of signals, the best established being light and food. However, circadian cycles are not simply the consequences of these two cues but are generated by endogenous circadian clocks. Indeed, clock machinery is found in mainly all tissues and cell types, including cells of the vascular system such as endothelial cells, fibroblasts, smooth muscle cells and stem cells. This machinery physiologically contributes to modulate the daily vascular function, and its disturbance therefore plays a major role in the pathophysiology of vascular dysfunction. Therapies targeting the circadian rhythm may therefore be of benefit against vascular disease.

"Summer Shift": A Potential Effect of Sunshine on the Time Onset of ST-Elevation Acute Myocardial Infarction

Background

ST‐elevation acute myocardial infarction (STEMI) represents one of the leading causes of death. The time of STEMI onset has a circadian rhythm with a peak during diurnal hours, and the occurrence of STEMI follows a seasonal pattern with a salient peak of cases in the winter months and a marked reduction of cases in the summer months. Scholars investigated the reason behind the winter peak, suggesting that environmental and climatic factors concur in STEMI pathogenesis, but no studies have investigated whether the circadian rhythm is modified with the seasonal pattern, in particular during the summer reduction in STEMI occurrence.

Methods and Results

Here, we provide a multiethnic and multination epidemiological study (from both hemispheres at different latitudes, n=2270 cases) that investigates whether the circadian variation of STEMI onset is altered in the summer season. The main finding is that the difference between numbers of diurnal (6:00 to 18:00) and nocturnal (18:00 to 6:00) STEMI is markedly decreased in the summer season, and this is a prodrome of a complex mechanism according to which the circadian rhythm of STEMI time onset seems season dependent.

Conclusions

The “summer shift” of STEMI to the nocturnal interval is consistent across different populations, and the sunshine duration (a measure related to cloudiness and solar irradiance) underpins this season‐dependent circadian perturbation. Vitamin D, which in our results seems correlated with this summer shift, is also primarily regulated by the sunshine duration, and future studies should investigate their joint role in the mechanisms of STEMI etiogenesis.

Daytime variation of perioperative myocardial injury in cardiac surgery and its prevention by Rev-Erbα antagonism: a single-centre propensity-matched cohort study and a randomised study

BACKGROUND

On-pump cardiac surgery provokes a predictable perioperative myocardial ischaemia-reperfusion injury which is associated with poor clinical outcomes. We determined the occurrence of time-of-the-day variation in perioperative myocardial injury in patients undergoing aortic valve replacement and its molecular mechanisms.

METHODS

We studied the incidence of major adverse cardiac events in a prospective observational single-centre cohort study of patients with severe aortic stenosis and preserved left ventricular ejection fraction (>50%) who were referred to our cardiovascular surgery department at Lille University Hospital (Lille, France) for aortic valve replacement and underwent surgery in the morning or afternoon. Patients were matched into pairs by propensity score. We also did a randomised study, in which we evaluated perioperative myocardial injury and myocardial samples of patients randomly assigned (1:1) via permuted block randomisation (block size of eight) to undergo isolated aortic valve replacement surgery either in the morning or afternoon. We also evaluated human and rodent myocardium in ex-vivo hypoxia-reoxygenation models and did a transcriptomic analysis in myocardial samples from the randomised patients to identify the signalling pathway(s) involved. The primary objective of the study was to assess whether myocardial tolerance of ischaemia-reperfusion differed depending on the timing of aortic valve replacement surgery (morning vs afternoon), as measured by the occurrence of major adverse cardiovascular events (cardiovascular death, myocardial infarction, and admission to hospital for acute heart failure). The randomised study is registered with ClinicalTrials.gov, number NCT02812901.

FINDINGS

In the cohort study (n=596 patients in matched pairs who underwent either morning surgery [n=298] or afternoon surgery [n=298]), during the 500 days following aortic valve replacement, the incidence of major adverse cardiac events was lower in the afternoon surgery group than in the morning group: hazard ratio 0·50 (95% CI 0·32-0·77; p=0·0021). In the randomised study, 88 patients were randomly assigned to undergo surgery in the morning (n=44) or afternoon (n=44); perioperative myocardial injury assessed with the geometric mean of perioperative cardiac troponin T release was significantly lower in the afternoon group than in the morning group (estimated ratio of geometric means for afternoon to morning of 0·79 [95% CI 0·68-0·93; p=0·0045]). Ex-vivo analysis of human myocardium revealed an intrinsic morning-afternoon variation in hypoxia-reoxygenation tolerance, concomitant with transcriptional alterations in circadian gene expression with the nuclear receptor Rev-Erbα being highest in the morning. In a mouse Langendorff model of hypoxia-reoxygenation myocardial injury, Rev-Erbα gene deletion or antagonist treatment reduced injury at the time of sleep-to-wake transition, through an increase in the expression of the ischaemia-reperfusion injury modulator CDKN1a/p21.

INTERPRETATION

Perioperative myocardial injury is transcriptionally orchestrated by the circadian clock in patients undergoing aortic valve replacement, and Rev-Erbα antagonism seems to be a pharmacological strategy for cardioprotection. Afternoon surgery might provide perioperative myocardial protection and lead to improved patient outcomes compared with morning surgery.

FUNDING

Fondation de France, Fédération Française de Cardiologie, EU-FP7-Eurhythdia, Agence Nationale pour la Recherche ANR-10-LABX-46, and CPER-Centre Transdisciplinaire de Recherche sur la Longévité.

Circadian Periodicity of Ischemic Heart Disease: A Systematic Review of the Literature

The authors performed a MEDLINE search to identify reports, published during the last 20 years, focused on circadian variation of acute myocardial infarction (AMI), and prevalence and the ratios between the number of events per hour during the morning and the other hours of the day were calculated. Despite the optimization of interventional and medical therapy of AMI since the first reports of circadian patterns in AMI occurrence, it was found that such a pattern still exists and that AMI happens most frequently in the morning hours.

Variation within Variation: Comparison of 24-h Rhythm in Rodent Infarct Size between Ischemia Reperfusion and Permanent Ligation

The detrimental effects of myocardial infarction in humans and rodents have a 24-h rhythm. In some human cohorts however, rhythmicity was absent, while the time of maximum damage differs between cohorts. We hypothesized that the type of damage influences the 24-h rhythm in infarct size. Myocardial infarction was induced in 12-week-old C57BL/six mice at four different time-points during the day using either permanent ligation (PL) or 30-min of ischemia followed by reperfusion (IR), with a control group wherein no ligation was applied. Infarct size was measured by echocardiography and histology at a 1-month follow-up. Rhythmicity in infarct size was present in the PL group at the functional and histological level, with maximal damage occurring when the infarct was induced at noon. In the IR group, no circadian rhythm was found. The time of the coronary artery ligation determines the outcome of myocardial infarction. Our data showed that in rodents, the presence of circadian rhythmicity and time of peak infarct size varies between experimental setups.

Myeloid Bmal1 deletion increases monocyte recruitment and worsens atherosclerosis

BMAL1, the nonredundant transcription factor in the core molecular clock, has been implicated in cardiometabolic diseases in mice and humans. BMAL1 controls the cyclic trafficking of Ly6chi monocytes to sites of acute inflammation. Myeloid deficiency of Bmal1 also worsens chronic inflammation in diet-induced obesity. We studied whether myeloid Bmal1 deletion promotes atherosclerosis by enhancing monocyte recruitment to atherosclerotic lesions. By generating Bmal1FloxP/FloxP;LysMCre mice on the Apoe-/- background, we showed that Bmal1 deletion in myeloid cells increased the size of atherosclerotic lesions. Bmal1 deficiency in monocytes and macrophages resulted in an increased total number of lesional macrophages in general and Ly6chi infiltrating monocyte-macrophages in particular, accompanied by skewed M2 to M1 macrophage phenotype. Ly6chi and/or Ly6clo monocyte subsets in blood, spleen, and bone marrow were not altered. Cell tracking and adoptive transfer of Ly6chi monocytes showed Bmal1 deficiency induced more trafficking of Ly6chi monocytes to atherosclerotic lesions, preferential differentiation of Ly6chi monocytes into M1 macrophages, and increased macrophage content and lesion size in the carotid arteries. We demonstrated that Bmal1 deficiency in macrophages promotes atherosclerosis by enhancing recruitment of Ly6chi monocytes to atherosclerotic lesions.-Huo, M., Huang, Y., Qu, D., Zhang, H., Wong, W. T., Chawla, A., Huang, Y., Tian, X. Y. Myeloid Bmal1 deletion increases monocyte recruitment and worsens atherosclerosis.

Circadian variation in acute myocardial infarct size assessed by cardiovascular magnetic resonance in reperfused STEMI patients

OBJECTIVE

Clinical studies using serum cardiac biomarkers to investigate a circadian variation in acute myocardial infarct (MI) size in ST-segment elevation myocardial infarction (STEMI) patients reperfused by primary percutaneous coronary intervention (PPCI) have produced mixed results. We aimed to investigate this phenomenon using acute MI size measured by cardiovascular magnetic resonance (CMR).

METHODS

Patient-level data was obtained from 4 randomized controlled trials investigating the MI-limiting effects of cardioprotective therapies in this pooled analysis. The primary analysis was performed in those patients with no pre-infarct angina; duration of ischemia >60min and <360min; Thrombolysis In Myocardial Infarction (TIMI) flow pre-PPCI ≤1; TIMI flow post-PPCI 3; and no collateral flow.

RESULTS

169 out of 376 patients with CMR data met the inclusion criteria for the primary analysis. A 24-hour circadian variation in acute MI size as a % of the area-at-risk (%AAR), after adjusting for confounders, was observed with a peak and nadir MI size in patients with symptom onset between 00:00 and 01:00 and between 12:00 and 13:00 respectively (difference from the average MI size 5.2%, 95%CI 1.1-9.4%; p=0.013). This was associated with a non-significant circadian variation in left ventricular ejection fraction (LVEF) (difference from the average LVEF 5.9%, 95%CI -0.6-2.2%, p=0.073). There was no circadian variation in MI size or LVEF in the whole cohort.

CONCLUSIONS

We report a circadian variation in acute MI size assessed by CMR in a subset of STEMI patients treated by PPCI, with the largest and smallest MI size occurring in patients with symptom onset between 00:00 and 01:00 and between 12:00 and 13:00 respectively.

On versus off-hour care of patients with acute coronary syndrome and persistent ST-segment elevation in certified German chest pain units

BACKGROUND

Regional healthcare projects improve the off-hour care of patients with acute coronary syndromes and persistent ST-segment elevation myocardial infarction (STEMI). To analyse differences in quality of care between on and off-hour care of STEMI patients admitted to certified German chest pain units.

METHODS

A total of 1107 STEMI patients from the German chest pain unit registry were enrolled. Analyses comprised critical time intervals (symptoms to first medical contact (FMC), FMC to admission, symptoms to admission, symptoms to balloon, FMC to balloon, door to balloon times) and major adverse cardiac and cerebrovascular events at follow-up.

RESULTS

54.8% of patients were admitted off-hours. Symptoms to admission (2:28 (1:28-5:20 h) vs. 3:16 h (1:35-8:06 h), P<0.001), symptoms to FMC (1:15 h (0:33-3:00 h) vs. 2:00 h (0:40-6:46 h), P<0.001) and FMC to admission intervals (0:45 h (0:30-1:20 h) vs. 0:52 h (0:32-1:35 h), P=0.09) were shorter during off-hours. Percutaneous revascularisation rates were high and without difference between on and off-hours (95.5% vs. 96.8%, P=0.30). Door to balloon times were significantly less during on-hours (0:32 h (0:18-1:06 h) vs. 0:44 h (0:23-1:20 h), P<0.01) without negative impact on the proportion of patients with a door to balloon time of <60 min (72.6% vs. 68.4%, P=0.19), symptoms to balloon (3:49 h (2:12-10:46 h) vs. 3:30 h (2:04-7:41 h), P=0.08) or FMC to balloon times (1:26 h (0:56-2:22 h) vs. 1:30 h (1:03-2:29 h), P=0.14). Major adverse cardiac and cerebrovascular event rates did not differ significantly between on and off-hours (log-rank test P=0.36).

CONCLUSIONS

The German chest pain unit network ensures rapid and structured preclinical and in-hospital care independent from the circadian variation of admission. Slower door to balloon times off-hours are compensated by faster symptoms to admission or symptoms to FMC intervals. Further efforts should focus on patient awareness programmes on-hours and STEMI alarming tracks off-hours.

Determinants of outcome in patients with chronic ischemic left ventricular dysfunction undergone percutaneous coronary interventions

Background

Percutaneous coronary interventions (PCI) in patients with ischemic systolic left ventricular dysfunction (SLVD) are routinely performed although their impact on prognosis remains unclear.

Methods

We retrospectively evaluated 385 consecutive patients (76 % male, 66 ± 9 years) with SLVD (left ventricular ejection fraction [LVEF] ≤40 %) due to chronic coronary artery disease, who underwent PCI between 1999 and 2009, and explored clinical factors associated with higher risk of death or of a composite of death and hospitalization for acute decompensated heart failure (ADHF).

Results

The median follow-up was 28 months (inter-quartile range 14–46 months). Death and the composite outcome of death and hospitalization for ADHF occurred in 80 (21 %) and 109 (28 %) patients respectively (8.4 and 11.5 per 100 patient-years of follow-up). Insulin-dependent diabetes mellitus (IDDM), multivessel disease, LVEF < 35 %, symptoms of heart failure (HF) emerged both as independent predictors of death (adjusted hazard ratios [HR] 2.64; 1.92, 1.88 and 1.67 respectively) and composite outcome of death and hospitalization for ADHF (adjusted HR 2.22, 1.92, 1.79 and 1.94 respectively). Furthermore advanced age (HR = 1.03) emerged as independent predictors of death and having performed a stress test before PCI correlated with reduced number of deaths and ADHF hospitalizations (HR = 0.60). Of note, PCI significantly reduced the symptom of angina from 63.2 % at baseline to 16.3 % at the last follow up (p < 0.0001).

Conclusions

IDDM, symptoms of HF, multivessel disease and LVEF < 35 % appear to be associated with worse outcome patients with ischemic SLVD undergoing PCI, and may be taken into account for optimal risk stratification. On the other hand, performing a stress testing before PCI seems to be associated with a more favorable outcome.

Circadian Dependence of Infarct Size and Acute Heart Failure in ST Elevation Myocardial Infarction

OBJECTIVES

There are conflicting data on the relationship between the time of symptom onset during the 24-hour cycle (circadian dependence) and infarct size in ST-elevation myocardial infarction (STEMI). Moreover, the impact of this circadian pattern of infarct size on clinical outcomes is unknown. We sought to study the circadian dependence of infarct size and its impact on clinical outcomes in STEMI.

METHODS

We studied 6,710 consecutive patients hospitalized for STEMI from 2006 to 2009 in a tropical climate with non-varying day-night cycles. We categorized the time of symptom onset into four 6-hour intervals: midnight-6:00 A.M., 6:00 A.M.-noon, noon-6:00 P.M. and 6:00 P.M.-midnight. We used peak creatine kinase as a surrogate marker of infarct size.

RESULTS

Midnight-6:00 A.M patients had the highest prevalence of diabetes mellitus (P = 0.03), more commonly presented with anterior MI (P = 0.03) and received percutaneous coronary intervention less frequently, as compared with other time intervals (P = 0.03). Adjusted mean peak creatine kinase was highest among midnight-6:00 A.M. patients and lowest among 6:00 A.M.-noon patients (2,590.8±2,839.1 IU/L and 2,336.3±2,386.6 IU/L, respectively, P = 0.04). Midnight-6:00 A.M patients were at greatest risk of acute heart failure (P<0.001), 30-day mortality (P = 0.03) and 1-year mortality (P = 0.03), while the converse was observed in 6:00 A.M.-noon patients. After adjusting for diabetes, infarct location and performance of percutaneous coronary intervention, circadian variations in acute heart failure incidence remained strongly significant (P = 0.001).

CONCLUSION

We observed a circadian peak and nadir in infarct size during STEMI onset from midnight-6:00A.M and 6:00A.M.-noon respectively. The peak and nadir incidence of acute heart failure paralleled this circadian pattern. Differences in diabetes prevalence, infarct location and mechanical reperfusion may account partly for the observed circadian pattern of infarct size and acute heart failure.

Myocardial infarct size and mortality depend on the time of day-a large multicenter study

BACKGROUND

Different studies have shown circadian variation of ischemic burden among patients with ST-Elevation Myocardial Infarction (STEMI), but with controversial results. The aim of this study was to analyze circadian variation of myocardial infarction size and in-hospital mortality in a large multicenter registry.

METHODS

This retrospective, registry-based study was based on data from AMIS Plus, a large multicenter Swiss registry of patients who suffered myocardial infarction between 1999 and 2013. Peak creatine kinase (CK) was used as a proxy measure for myocardial infarction size. Associations between peak CK, in-hospital mortality, and the time of day at symptom onset were modelled using polynomial-harmonic regression methods.

RESULTS

6,223 STEMI patients were admitted to 82 acute-care hospitals in Switzerland and treated with primary angioplasty within six hours of symptom onset. Only the 24-hour harmonic was significantly associated with peak CK (p = 0.0001). The maximum average peak CK value (2,315 U/L) was for patients with symptom onset at 23:00, whereas the minimum average (2,017 U/L) was for onset at 11:00. The amplitude of variation was 298 U/L. In addition, no correlation was observed between ischemic time and circadian peak CK variation. Of the 6,223 patients, 223 (3.58%) died during index hospitalization. Remarkably, only the 24-hour harmonic was significantly associated with in-hospital mortality. The risk of death from STEMI was highest for patients with symptom onset at 00:00 and lowest for those with onset at 12:00.

DISCUSSION

As a part of this first large study of STEMI patients treated with primary angioplasty in Swiss hospitals, investigations confirmed a circadian pattern to both peak CK and in-hospital mortality which were independent of total ischemic time. Accordingly, this study proposes that symptom onset time be incorporated as a prognosis factor in patients with myocardial infarction.

Independent association between symptom onset time and infarct size in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention

Recent studies have reported on circadian variation in infarct size in ST-elevation myocardial infarction (STEMI) patients. Controversy remains as to whether this finding indicates circadian dependence of myocardial tolerance to ischemia/reperfusion injury or that it can simply be explained by confounding factors such as baseline profile and ischemic time. We assessed the clinical impact and independent association between symptom onset time and infarct size, accounting for possible subgroup differences. From a multicenter registry, 6799 consecutive STEMI patients undergoing primary percutaneous coronary intervention (PCI) between 2004 and 2010 were included. Infarct size was measured using peak creatine kinase (CK). Infarct size exhibited circadian variation with largest infarct size in patients with symptom onset around 03:00 at night (estimated peak CK 1322 U/l; 95% confidence interval (CI): 1217-1436) and smallest infarct size around 11:00 in the morning (estimated peak CK 1071 U/l; 95% CI: 1001-1146; relative reduction 19%; p = 0.001). Circadian variation in infarct size followed an inverse pattern in patients with prior myocardial infarction (p-interaction <0.001) and prior PCI (p-interaction = 0.006), although the later did not persist in multivariable analysis. Symptom onset time remained associated with infarct size after accounting for these interactions and adjusting for baseline characteristics and ischemic time. Symptom onset time did not predict one-year mortality (p = 0.081). In conclusion, there is substantial circadian variation in infarct size, which cannot be fully explained by variations in baseline profile or ischemic time. Our results lend support to the hypothesis of circadian myocardial ischemic tolerance and suggest a different mechanism in patients with prior myocardial infarction.

Calcineurin and its regulator, RCAN1, confer time-of-day changes in susceptibility of the heart to ischemia/reperfusion

Many important components of the cardiovascular system display circadian rhythmicity. In both humans and mice, cardiac damage from ischemia/reperfusion (I/R) is greatest at the transition from sleep to activity. The causes of this window of susceptibility are not fully understood. In the murine heart we have reported high amplitude circadian oscillations in the expression of the cardioprotective protein regulator of calcineurin 1 (Rcan1). This study was designed to test whether Rcan1 contributes to the circadian rhythm in cardiac protection from I/R damage. Wild type (WT), Rcan1 KO, and Rcan1-Tg mice, with cardiomyocyte-specific overexpression of Rcan1, were subjected to 45min of myocardial ischemia followed by 24h of reperfusion. Surgeries were performed either during the first 2h (AM) or during the last 2h (PM) of the animal's light phase. The area at risk was the same for all genotypes at either time point; however, in WT mice, PM-generated infarcts were 78% larger than AM-generated infarcts. Plasma cardiac troponin I levels were likewise greater in PM-operated animals. In Rcan1 KO mice there was no significant difference between the AM- and PM-operated hearts, which displayed greater indices of damage similar to that of PM-operated WT animals. Mice with cardiomyocyte-specific overexpression of human RCAN1, likewise, showed no time-of-day difference, but had smaller infarcts comparable to those of AM-operated WT mice. In vitro, cardiomyocytes depleted of RCAN1 were more sensitive to simulated I/R and the calcineurin inhibitor, FK506, restored protection. FK506 also conferred protection to PM-infarcted WT animals. Importantly, transcription of core circadian clock genes was not altered in Rcan1 KO hearts. These studies identify the calcineurin/Rcan1-signaling cascade as a potential therapeutic target through which to benefit from innate circadian changes in cardiac protection without disrupting core circadian oscillations that are essential to cardiovascular, metabolic, and mental health.

Novel therapeutic strategies for cardioprotection

The morbidity and mortality from ischemic heart disease (IHD) remain significant worldwide. The treatment for acute myocardial infarction has improved over the past decades, including early reperfusion of occluded coronary arteries. Although it is essential to re-open the artery as soon as possible, paradoxically this leads to additional myocardial injury, called acute ischemia-reperfusion injury (IRI), for which currently no effective therapy is available. Therefore, novel therapeutic strategies are required to protect the heart from acute IRI in order to reduce myocardial infarction size, preserve cardiac function and improve clinical outcomes in patients with IHD. In this review article, we will first outline the pathophysiology of acute IRI and review promising therapeutic strategies for cardioprotection. These include novel aspects of mitochondrial function, epigenetics, circadian clocks, the immune system, microvesicles, growth factors, stem cell therapy and gene therapy. We discuss the therapeutic potential of these novel cardioprotective strategies in terms of pharmacological targeting and clinical application.

Tick-tock: is your cardiometabolic risk on the clock?

Governing a large amount of cellular processes in mammalian cells is a 24-h regulatory mechanism known as the circadian clock. Through the release of neurohormonal factors, the master central clock is able to regulate the otherwise independent peripheral clocks situated in all vital organs. It has recently been shown that forced misalignment of the circadian cycles, often as a consequence of lifestyle factors, is an independent cardiometabolic risk factor and may thus potentially predispose certain groups, such as nightshift workers, to cardiovascular disease. In this review, we will analyse some of the recent advances regarding circadian clock dysfunction and the development of cardiovascular diseases. Finally, we will touch on the developing link between circadian dysfunction and myocardial infarctions.

Fever after primary percutaneous coronary intervention in ST-segment elevation myocardial infarction is associated with adverse outcomes

BACKGROUND

Fever is a common finding after primary percutaneous coronary intervention (PPCI) in patients with ST-segment elevation myocardial infarction (STEMI). However, its prognostic value is not validated yet.

OBJECTIVES

This study sought to evaluate the impact of fever after PPCI in STEMI on adverse clinical outcomes.

METHODS

Five hundred fourteen consecutive patients who underwent PPCI due to STEMI were enrolled. Body temperature (BT) was checked every 6 h for 5 days after PPCI. Patients were divided into two groups according to the highest quartile of peak BT; peak BT≤37.6 °C (control group) and peak BT>37.6 °C (fever group). Rates of 1-year major adverse cardiovascular events (MACE; death, myocardial infarction, any revascularization) were compared.

RESULTS

The prevalence of fever group (peak BT>37.6 °C) was 24.7% (127/514). White blood cell count, highly sensitive C-reactive protein and serum cardiac troponin I level were higher in fever group than control group (12,162±4199/μL vs. 10,614±3773/μL, p<0.001; 22.9±49.4 mg/L vs. 7.4±2.5 mg/L, p=0.001, 16.7±36.9 ng/dl vs. 8.70±26.2 ng/dl, p=0.027, respectively). The frequency of a history of previous myocardial infarction and left ventricular ejection fraction was lower in fever group (0.0% vs. 4.7%, p=0.010; 47±8 % vs. 49±9 %, p=0.002, respectively). There was no significant difference in angiographic characteristics between 2 groups. 1-year MACE rates were higher in fever group (11.0% vs. 4.7%, p=0.010). Multivariate analysis revealed fever (OR 2.358, 95% CI 1.113-4.998, p=0.025), diabetes mellitus as risk factor (2.227, 1.031-4.812, 0.042), and left anterior descending artery as infarct related artery (2.443, 1.114-5.361, 0.026) as independent predictors for 1-year MACE.

CONCLUSIONS

Fever after PPCI in patients with STEMI is frequently developed and it can predict adverse clinical outcome.