The Effect of Population Age and Climate on COVID-19 Morbidity and Mortality.

BACKGROUND: The novel coronavirus disease 2019 (COVID-19) is an infectious disease that presents an urgent challenge to global health and economy. OBJECTIVES: To assess the effects of population median age and mean ambient temperature on the COVID-19 global pandemic burden. METHODS: We used databases from open access public domains to record population median age, mean ambient temperature, and the numbers of COVID-19 cases and deaths on days 14 and 28 from the pandemic outbreak for each country in the world. We then calculated the correlation between these parameters. RESULTS: The analysis included 202 countries. A univariate analysis showed that population median age significantly correlated with the cumulative number of cases and deaths, while mean ambient temperature showed a significant inverse correlation with the cumulative number of deaths on days 14 and 28 from the epidemic outbreak. After a multivariate logistic regression analysis only population median age retained its statistically significant correlation. CONCLUSIONS: Country population median age significantly correlated with COVID-19 pandemic burden while mean ambient temperature shows a significant inverse correlation only in univariate analysis. Countries with older populations encountered a heavier burden from the COVID-19 pandemic. This information may be valuable for health systems in planning strategies for combating this global health hazard.

[Incidence and predictors of atrial fibrillation after coronary artery bypass grafting in the Negev--are we different from the rest of the world?].

BACKGROUND: Atrial fibrillation (AF) remains a common problem after coronary artery bypass grafting (CABG). AF increases the risk for stroke and is associated with increased length of hospitalization and mortality. AIM: This study aimed to determine incidence, timing and predictors of post CABG AF in a prospectively evaluated cohort of patients undergoing CABG in the Negev. METHODS: Preoperative clinical data, intraoperative, intensive care and postoperative events including AF episodes were prospectively evaluated in 156 consecutive patients undergoing CABG during a nine month period ending on July 2003. RESULTS: Mean age was 64.9 years (SD = 9.7, range 41 - 84 years); 76.3% (119) were male. The in-hospital mortality was 1.2% (2 patients). The incidence of AF was 32.1% (50), with 40% of the AF episodes occurring on the second postoperative day (range 1-6 days). Univariate analyses identified the following variables as risk factors for AF: female gender, older age, ethnic origin, BMI > 30, hypertension, dyslipidemia, pre CABG nitrate, Ca blockers and furosemide treatment, left atrial diameter, renal failure and post CABG respiratory complications (p <0.05). By multivariate analysis, three variables were identified as independent predictors: BMI>30 (odds ratio 2.4; 95% CI 1.2-4.8); Sephardic Jews (OR 11.2; CI 1.0-114); enlarged left atrium (OR 4.6; CI 1.5-14.1). CONCLUSIONS: Consistent with previous studies, enlarged left atrium was a predictor of post CABG AF. In addition ethnic origin (Sephardic Jews) and BMI> 30 were also found to be important predictors of post CABG AF. In comparison with other studies, we not found moderate differences in outcomes and mortality in population that underwent CABG in the Negev in comparison to studies of the world.

Atrial fibrillation and plasma troponin I elevation after cardiac surgery: relation to inflammation-associated parameters.

BACKGROUND: Recent studies have demonstrated correlation between inflammation to plasma troponin (cTnI) levels elevation and atrial fibrillation (AF) in noncardiac surgery settings. The goal of this prospective study was to examine the relation between inflammation associated parameters (IAPs) to post cardiac surgery cTnI elevation and AF. METHODS: A single post CABG cTnI measurement was assessed in 156 consecutive patients. Clinical, operative and postoperative data, IAPs (hypophosphatemia, preoperative statin treatment, immediate postoperative fever, and prolonged mechanical ventilation) and in-hospital AF episodes were prospectively recorded. RESULTS: Mean cTnI level was 14.4 +/- 12.4 ng/mL. In the two in-hospital deaths (1.2%) cTnI concentration was less than 12 ng/mL. Cardiac troponin-I levels were significantly higher in patients not preoperatively treated with statins (21.6 +/- 4.1 vs. 13.3 +/- 0.9, p = 0.05), in patients who needed intraoperative cardioversion (16.7 +/- 2.2 vs. 12.2 +/- 0.9, p = 0.07), in patients with postoperative hypophosphatemia (16.9 +/- 10.0 vs. 11.1 +/- 13.7, p = 0.04), postoperative fever (18.6 +/- 3.0 vs. 13.7 +/- 1.0, p = 0.07) and postoperative respiratory complications (23.9 +/- 4.3 vs. 13.5 +/- 1.0, p = 0.04). Step-wise logistic regression analysis revealed the following parameters as independently associated with elevated cTnI levels: preoperative statin treatment (CI 95%-15.9; -1.7, p = 0.02), intraoperative ventricular arrhythmia (CI 95%-0.7; 13.8, p = 0.08), hypophosphatemia (CI 95% 0.9; 8.6, p = 0.02), postoperative fever (CI 95% 0.9; 11.0, p = 0.02), and postoperative respiratory complications (CI 95% 0.1; 0.5, p = 0.01). Of the 156 patients, 50 (32.1%) had postoperative AF. The first episode of AF occurred between postoperative day 1 and 6 (mean-day 2). Mean duration of AF was 21.8 +/- 8.1 hours. Postoperative AF was significantly associated with age above 75 (50% vs. 29.4%, p = 0.01), hypertension (37% vs. 18%, p = 0.02), preoperative calcium channel blockers treatment (44% vs. 26%, p = 0.02), furosemide treatment (58% vs. 30%, p = 0.05), and preoperative left atrial diameter above 40 mm (56% vs. 29%, p = 0.01). Postoperatively, AF was significantly associated with postoperative renal failure (70% vs. 29%, p = 0.01), respiratory complications (61% vs. 29%, p = 0.02), and prolonged hospital stay (OR 1.1; CI 1.0-1.3; p < 0.05). No association was found between troponin levels and postoperative AF. Multivariable analysis found only left atrial enlargement and prolonged hospital stay independently associated with AF. CONCLUSIONS: A significant correlation between clinical IAPs and cTnI plasma level elevation was found after cardiac surgery. There was no correlation between these parameters and postoperative AF, and there was no correlation between postoperative plasma cTnI levels and the occurrence of AF. Preoperative treatment with statins may be beneficial in reducing postoperative inflammatory response but further study has to be carried out.

Plasma troponin levels after cardiac surgery vs after myocardial infarction.

Raised plasma troponin, a diagnostic marker for myocardial infarction, usually occurs after cardiac surgery, leading to difficulties in diagnosing postoperative myocardial infarction. To ascertain whether the same processes influence troponin elevation in both conditions, a literature search was performed for plasma troponin elimination curves after myocardial infarction, myocardial infarction with reperfusion, and cardiac surgery. From 70 studies, 11 curves using the Stratus immunoassay kit were analyzed: 5 post-cardiac surgery (412 patients), 2 after myocardial infarction with reperfusion (169 patients), and 4 after myocardial infarction (640 patients). For each group, a new plot was formulated from the mean troponin level at each time interval. While the up-slope of the cardiac surgery curve was much steeper than that of myocardial infarction, resembling that of myocardial infarction with reperfusion, its down-slope was significantly more gentle than that of both other groups (-0.91 vs -5.31, t = 3.47, df = 8, p < 0.01). This suggests that postoperative troponin elevation involves enhanced cell permeability as seen after ischemia reperfusion rather than permanent cellular damage. The gentler down-slope may point to surgery-induced impaired troponin removal from the circulation. Due to the different mechanisms proposed, implications from post-myocardial infarction troponin levels may not be conferred on post-cardiac surgery patients.

Timing of chest tube removal after coronary artery bypass surgery.

AIM: Assessing the impact of chest tube removal timing following a coronary artery bypass grafting surgery on the clinical outcome. METHODS: Eighty-three consecutive patients were randomly assigned to either have the chest tube removed 24 hours (Group A) or 48 hours (Group B) postoperatively. Chest tubes were removed on the condition that drainage was less than 100 cc for the last 8 hours. Pre- and postoperative data were analyzed. RESULTS: The following preoperative and intraoperative risk factors were more prevalent among Group A patients: previous MI (60.5% vs 40.7%, p = 0.11), previous CVA (9.1% vs 0%, p = 0.11), hypertension (72.7% vs 55.6%, p = 0.14), pump time (111.6 min vs 96.8 min, p = 0.07), and cross-clamp time (73.8 min vs 64.4 min, p = 0.07). Postoperatively, there was a lower demand for analgesics in Group A (2.1 times for 12 hours at 36 hours vs 3.6 p = 0.09), lower white blood cell count (10,947 at 48 hours vs 11,576, p = 0.39) a higher oxygen saturation (91.9% at 48 hours vs 88.9%, p = 0.07), higher expiratory volumes (594 mL at 36 hours vs 514 mL p = 0.08) and earlier mobilization (23% walking at 48 hours vs 4%, p = 0.01). Pleural effusion and atelectasis were less frequent in Group A in both chest X-rays (66% vs 73%, p = 0.6 and 64% vs 75%, p = 0.47, respectively) and CT scans (19% vs 41%, p = 0.1 and 84% vs 96%, p = 0.42, respectively). There was no difference between the two groups in the prevalence of serous wound discharge and the length of hospital stay and there were no reported cases of pneumonia throughout the study. CONCLUSION: In cases where no excessive drainage accumulates, early removal of the chest tubes was found to be a policy that improves the postoperative outcome and decreases the need for supportive treatment such as analgetics, physiotherapy, nurse care, and oxygen. This policy did not involve significant residual effusions.

Post-reperfusion rapidly progressive glomerulonephritis in post-transplant IgA nephropathy.

Rapidly progressive glomerulonephritis (RPGN) is a rare occurrence in IgA nephropathy (IgAN) in renal transplant patients on immunosuppressive therapy. RPGN post ischemia-reperfusion has not been previously reported. We report a 62 year old male patient on azathioprine therapy, 9 years after left cadaveric renal transplantation due to end stage renal disease of unknown etiology, who presented with progressive deterioration in renal function and hematuria. Renal biopsy was consistent with IgAN. Duplex and CT scan demonstrated a decreased renal graft perfusion, due to severe atherosclerosis and stenosis of iliac arteries. The patient underwent left axilo-femoral bypass graft surgery with improvement in kidney graft perfusion and function. However, few weeks later, patient presented with pulmonary edema and advanced renal failure and he was initiated on hemodialysis. Repeated renal biopsy demonstrated crescentic GN. To the best of our knowledge, this is the first report of RPGN following reversal of ischemia and reperfusion. There was no evidence for atherembolic disease which is not uncommon after vascular surgery and it has been reported to be rarely associated to crescentic GN. Theoretical explanations for exacerbation of IgAN to crescentic GN, following successful reperfusion, could be enhancement of capillary damage, inflammation and oxidative stress. Putative mechanisms for these phenomena may be interaction of reperfusion-induced hyperfiltration, high intraglomerular capillary pressure, oxidative stress, increased polymorphonucler cells infiltration and inflammation; the presence of IgA immune deposits and azathioprine metabolites, both can also be associated to enhancement of oxidative stress.

Should we give prophylactic renal-dose dopamine after coronary artery bypass surgery?

OBJECTIVE: A prospective double-blind randomized study undertaken to assess the effect of postoperative prophylactic "renal-dose" dopamine on post-coronary artery bypass grafting surgery's clinical outcome. METHODS: Eighty-five consecutive patients undergoing CABG operation were randomized to receive either 3-5 microg/kg/min dopamine (group D, n = 41) or saline as placebo (group P, n = 45) for 48 postoperative hours. Clinical outcome parameters were collected for four postoperative days. RESULTS: Preoperative and operative parameters were similar in both groups. Four patients from group P and none from group D reached an end-point of the study (oliguria, renal dysfunction) and received dopamine. Two patients from group P and none from group D needed an additional inotropic support. Mean arterial pressure values were similar during the first 24 hours after operation, but left atrial pressure values tended to be higher in group P (10 +/- 4 vs 7 +/- 3 mmH2O, p = 0.18). The mean pH was higher in group D at 8 hours after operation (7.38 +/- 0.2 vs 7.36 +/- 0.3, p = NS), due to higher bicarbonate levels (23 +/- 2 mmol/l vs 21 +/- 2, p = 0.49). The incidence of lung congestion in chest X-rays and CT scans was significantly higher in group P (50% vs 29%, p = 0.073 at 48 hours postoperatively). Room air blood O2 saturation and maximal expiratory volume tended to be higher in group D (at 72 hours after operation- 92 +/- 4 vs 90%+/- 5, p = 0.29 and 646 +/- 276 vs 485 ml +/- 206, p = 0.16, respectively). There was no statistical difference in urine output but the amount of furosemide given to patients in group P was significantly higher (during the first 8 hours 2.5 +/- 0.5 vs. 0.3 mg +/- 1.6, p = 0.07). Plasma creatinine levels were significantly lower in group D (at 24 hours 0.93 +/- 0.02 vs 1.05 mg/dL +/- 0.02, p = 0.02). Mobilization after surgery was faster in group D. CONCLUSIONS: Prophylactic dopamine administration after coronary artery bypass grafting surgery improves patient hemodynamic and renal status, reduces the need for additional medical support (inotropes and furosemide) and thus, provides stable postoperative course.

The influence of cardiopulmonary bypass flow characteristics on the clinical outcome of 1820 coronary bypass patients.

OBJECTIVE: To determine whether pulsatile perfusion is clinically beneficial for adult cardiac operations. METHODS: Data concerning consecutive patients undergoing isolated coronary bypass surgery (n=1820) from January 1, 1997 to July 31, 1999 were reviewed. RESULTS: Nine hundred fifteen patients received pulsatile perfusion (PP) while perfusion in the remaining 905 patients was nonpulsatile (NP). Patients in the PP group were older (64.0 +/- 9.2 years versus 63.1 +/- 9.9 years) and experienced more of the following: urgent operations (42.4% versus 38.0%), preoperative intra-aortic balloon pump (4.8% versus 1.8%), preoperative cerebrovascular accidents (CVA; 3.1% versus 1.3%) and renal insufficiency (10.5% versus 7.0%). The PP group had higher incidence of early postoperative mortality (2.6% versus 1.5%), CVA (3.1% versus 1.3%), need for dialysis (3.2% versus 2.2%) and longer hospital stay (9.2 +/- 8.3 days versus 8.5 +/- 5.8 days). The incidence of postoperative myocardial infarction and renal dysfunction was similar in both groups (2.0% versus 2.2% and 3.3% versus 3.9% respectively; not significant). Because of the significant difference in preoperative parameters for the PP and NP groups, the following three statistical techniques were used to isolate the effect of perfusion characteristics on operative outcome: multiple regression, propensity score and risk stratification. Multivariate analysis did not find PP to be protective against mortality, morbidity and mortality, and CVA or for the development of postoperative renal dysfunction. When propensity score analysis was applied, the incidence of cardiac morbidity and mortality was strongly associated with the quintile (first quintile 6.7%, fifth quintile 27.0%, P<0.001). Multivariate analysis including quintiles did not find PP to be an independent predictor for mortality or for morbidity and mortality. Risk stratification was performed for age and for preoperative creatinine clearance levels. In all groups, PP did not seem to reduce the incidence of morbidity, morbidity and mortality, or the development of postoperative renal dysfunction. In patients with preoperative renal dysfunction, mean postoperative creatinine levels and the need for dialysis following surgery were similar in the PP and NP groups. CONCLUSION: Pulsatile flow does not appear to offer any clinical benefit over nonpulsatile flow for cardiac surgery patients.

Impact of preoperative renal dysfunction on cardiac surgery results.

Results of cardiac surgery were analyzed using a database that included plasma creatinine levels in 2,214 patients, of whom 507 had preoperative renal dysfunction (creatinine clearance < 0.9 mL x s(-1) x m(-2)). Logistic regression and propensity score analyses found preoperative renal dysfunction to be an independent predictor of morbidity and mortality. Plotting preoperative creatinine clearance against morbidity and mortality revealed an exponential increase in morbidity and mortality when preoperative creatinine clearance was < 0.84 mL x s(-1) x m(-2). Patients were stratified for age, operative procedure, and comorbidity. In all stratified groups, preoperative creatinine clearance < 0.84 mL x s(-1) x m(-2) was associated with similar exponential increases in morbidity and mortality. In patients with preoperative renal dysfunction, elevated plasma creatinine levels persevered for 6 months postoperatively. Dialysis beyond postoperative day 10 was required in < 2% of patients with preoperative plasma creatinine of 160-200 micro mol x L(-1) and in 5% in those with creatinine > 200 micro mol x L(-1) (p < 0.05). Actuarial survival was significantly reduced (< 90% at 18 months postoperatively) in patients with preoperative renal dysfunction.

Colchicine for the prevention of postpericardiotomy syndrome.

BACKGROUND: Postpericardiotomy syndrome (PPS) is a troublesome complication of cardiac surgery, occurring in 10-45% of cases. Accepted modalities of treatment include nonsteroidal anti-inflammatory drugs, corticosteroids, and pericardiectomy in severe cases. The optimal method for prevention of PPS has not been established. Recent trial data have shown that colchicine is efficient in the secondary prevention of recurrent episodes of pericarditis. The aim of the present study was to evaluate the possible benefit of colchicine for the primary prevention of PPS in patients after cardiac surgery. To the best of our knowledge, this is the first study addressing this issue. PATIENTS AND METHODS: A prospective, randomized, double-blind design was used. The initial study group included 163 patients who underwent cardiac surgery in two centers in Israel between October 1997 and September 1998. On the 3rd postoperative day, the patients were randomly assigned to receive colchicine (1.5 mg/day) or placebo for 1 month. All were evaluated monthly for the first 3 postoperative months for development of PPS. RESULTS: 52 of the 163 patients were excluded because of postoperative complications, noncompliance, or gastrointestinal side effects of treatment. Of the 111 patients who completed the study, 47 (42.3%) received colchicine and 64 (57.7%) placebo. There was no statistically significant difference between the groups in clinical or surgical characteristics. PPS was diagnosed in 19 patients (17.1%), 5/47 cases (10.6%) in the colchicine group and 14/64 (21.9%) in the placebo group. The difference showed a trend toward statistical significance (p < 0.135). CONCLUSIONS: Colchicine may be efficacious for the prevention of PPS in patients after cardiac surgery. Further evaluations in larger clinical trials are warranted.