A study to establish international diagnostic reference levels for paediatric computed tomography.

The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDIw, CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75th percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided.

In-hospital complications and 1-year outcome of acute coronary syndrome in patients with hypertension: findings from the 2nd Gulf Registry of Acute Cardiac Events.

Using data from the 2nd Gulf Registry of Acute Coronary Events (Gulf RACE-2) in 2008-09 we investigated the in-hospital complications and 1-year outcome of acute coronary syndrome (ACS) in patients with systemic hypertension from 6 Gulf countries. Of 7847 consecutive patients admitted with ACS, 3746 (47.7%) had hypertension. Hypertension was more prevalent in women, in Arabs than non-Arabs and in older age groups. Patients with hypertension were more likely than those without hypertension to present with dyspnoea and advanced Killip class. Among hypertensive patients, the mortality rate was higher only among those admitted with ST-elevation myocardial infarction. After adjustment for baseline variables, hypertension was an independent predictive factor for heart failure (OR = 1.31) and stroke (OR = 2.47). here were no significant differences in mortality in hypertensive ACS patients when stratified by sex, age or ethnicity.

In-hospital complications and 1-year outcome of acute coronary syndrome in patients with hypertension: findings from the 2nd Gulf registry of acute cardiac events

Using data from the 2nd Gulf Registry of Acute Coronary Events [Gulf RACE-2] in 2008-09 we investigated the in-hospital complications and 1-year outcome of acute coronary syndrome [ACS] in patients with systemic hypertension from 6 Gulf countries. Of 7847 consecutive patients admitted with ACS, 3746 [47.7%] had hypertension. Hypertension was more prevalent in women, in Arabs than non-Arabs and in older age groups. Patients with hypertension were more likely than those without hypertension to present with dyspnoea and advanced Killip class. Among hypertensive patients, the mortality rate was higher only among those admitted with ST-elevation myocardial infarction. After adjustment for baseline variables, hypertension was an independent predictive factor for heart failure [OR = 1.31] and stroke [OR = 2.47]. There were no significant differences in mortality in hypertensive ACS patients when stratified by sex, age or ethnicity

Cardiovascular risk assessment among potential kidney transplant candidates and perioperative outcome: analysis of 75 consecutive Middle Eastern patients.

BACKGROUND: Evaluation of coronary artery disease (CAD) is a nonstandardized practice before kidney transplantation. The aim of this study was to assess the adequacy of cardiovascular investigations in relation to cardiovascular outcomes of Middle Eastern patients undergoing renal transplantation. METHODS: Seventy-five consecutive patients with end-stage renal disease in Qatar were prospectively evaluated between April 2005 and March 2008. They subsequently underwent kidney transplantation. Our prespecified protocol utilized noninvasive and/or invasive tests for the evaluation. RESULTS: The median age was 51 years including 68% men, and 87% of patients maintained on dialysis. Overall, 21 (28%) patients showed evidence of CAD, an incidence that was much higher among patients with diabetes (81%). There were 13 (17%) subjects shown to have CAD by coronary angiography in the absence of a background CAD history. The perioperative cardiovascular course was uneventful in the majority of patients except for five who developed acute coronary syndrome without mortality. CONCLUSION: This study confirmed the high incidence of CAD among kidney transplant candidates. Myocardial perfusion testing was not predictive of perioperative cardiac events. The incidence of perioperative cardiac complications was low; five patients (6.6%) developed acute coronary syndrome. This study suggested that kidney transplantation can be performed safely in the majority of patients regardless of age and even among those with prior evidence of CAD.

Is there any effect of Ramadan fasting on stroke incidence?

INTRODUCTION: Over one billion Muslims fast worldwide during the month of Ramadan. Fasting during Ramadan is a radical change in lifestyle for the period of a lunar month. The objective of this study was to investigate whether Ramadan fasting has any effect on the incidence of stroke and its outcome in a geographically-defined population. METHODS: We retrospectively reviewed a 13-year stroke database and studied the data on Muslim patients who were hospitalised with stroke over a 13-year period from January 1991 to December 2003. Patients were divided according to the time of presentation in relation to the month of Ramadan, one month before, during, and one month after Ramadan. The number of hospitalisations for stroke in various time periods was analysed. The age of presentation, gender, cardiovascular risk factor profiles (smoking status, hypertension, hypercholesterolaemia, diabetes mellitus, and pre-existing cardiovascular disease) were analysed. We also studied the trends of in-hospital mortality, morbidity and acute medical care provided. RESULTS: Overall, 335 Muslim patients were hospitalised for stroke. Their mean age and standard deviation were 56.99 and 13.9 years, respectively. The number of hospitalisations for stroke was not significantly different in the month of Ramadan (29 cases), when compared to the month before Ramadan (30 cases) and the month after Ramadan (29 cases). Risk factors included for stroke were not significantly different in Ramadan when compared to the month before and after Ramadan. These associated diseases were hypertension, diabetes mellitus, hypercholesterolaemia, acute myocardial infarction, and congestive heart failure. CONCLUSION: This study demonstrated that no significant difference was found in the number of hospitalisations for stroke while fasting during the month of Ramadan when compared to the non-fasting months.

Does the circadian pattern for acute cardiac events presentation vary with fasting?

BACKGROUND: Over one billion Muslims fast worldwide during the month of Ramadan. The impact of fasting on circadian presentation with acute cardiac events is unknown. AIM: To determine if fasting has any effect on the circadian presentation of acute cardiac events. SETTING AND DESIGN: A prospective study in a general hospital. MATERIALS AND METHODS: Patients with acute coronary events were divided into two groups based on the history of fasting. Information about age, gender, cardiovascular risk factor profiles and outcome was collected. The relationship of time of presentation of initial symptoms with fasting was evaluated using Student's t-test, Mann-Whitney U-test and chi2 analysis. RESULTS: Of the 1019 patients hospitalized during the study period, 162 were fasting. Although, fasting patients were more likely to present to the emergency department in the time periods 5-6 AM (10.5% vs 6.3%) and 11 PM (11.1% vs 7.1%) and were less likely to present in the time periods 1-2 PM (3.7% vs 7.2%) and 5-6 PM (3.7% vs 7.0%); these differences were not statistically significant. Fasting patients were less likely to have their symptoms start between 5 and 8 AM (11.1% vs 19.4%) and more likely to have symptoms between 5 and 6 PM (11.1% vs 6.0%) and 3 and 4 AM (11.1% vs 6.9%). These differences for time of initial symptoms were statistically significant (P=0.002). CONCLUSION: Exogenous factors associated with fasting, namely, the changes in food intake and/or sleep timings, affect the circadian rhythm and influence the timing of presentation of acute coronary events.

Is hypertension a predictor for heart failure? A cross cultural comparison over a 10-year period.

This was a retrospective cohort study to assess the effect of hypertension (HTN) among Qatari and Asian patients admitted to the Hamad General Hospital in Qatar with heart failure (HF) and to identify risk factors that contribute to the development of HF in HTN patients in the State of Qatar. A total of 20,856 patients were treated during the 10-year period; 8446 were Qataris and 60% were male. Among the total Qatari patients admitted with HF (n=2342), 52.4% had HTN. The incidence of HTN was slightly higher in males than in females (50.4 vs. 49.6%; p<0.001). Significantly more HTN patients had diabetes mellitus (DM) (p<0.001) and hypercholesterolemia (p<0.001). There was also a significant difference between Qatari and Asian HTN patients in respect of their age (p<0.001) and gender (p<0.001). Qatari hypertensive patients were more likely to have DM (p<0.001). HTN and DM were the most common risk factors for HF.

Thrombolytic therapy use for acute myocardial infarction and outcome in Qatar.

OBJECTIVE: Data on the outcome of patients treated with thrombolytic therapy in the Arab world is scarce. The main objective of this study is to study the 7-day morbidity and mortality rate and the rate of use of thrombolytic therapy in patients presenting with acute myocardial infarction treated with thrombolytic therapy in the Middle East. METHODS: We conducted a retrospective analysis of prospectively collected data for all patients who were admitted to Coronary Care Unit in Cardiology Department in Hamad Medical during the period (1991-2001). Patients were divided into two groups in relation to ethnicity whether they received thrombolysis or not. In each group, the number of patients, age at the time of admission, gender, cardiovascular risk profile, therapy and outcome in regard of in-hospital complication and 7-day death as primary end point were analyzed. RESULTS: Of the total 5388 patients admitted with acute myocardial infarction during the 10-year period, 66.3% (3567) with STE MI were found, 61.4% (2190) of them received thrombolytic therapy while 38.6% (1377) were not eligible for thrombolytic therapy. The remaining 33.7% (1821) were admitted with non-STE MI. In consideration of ethnic variation, patients with STE MI eligible for thrombolytic therapy, 29.6% (1598) were Qataris and 70.4% (3792) were non-Qataris. Thrombolytic therapy was administered to 25.9% (414) of Qatari patients and 51.3% (1947) of non-Qataris. The mortality rate of Qatari patients who received thrombolytic therapy was 9.2% (38) vs. 19.5% (231) who did not receive thrombolytic therapy (p<0.001). In non-Qatari patients, the mortality rate was 5.2% (102) for those who received thrombolytic therapy, while it was 8.6% (159) for those with no thrombolytic therapy (p<0.001). When compared to male patients, female patients with thrombolytic therapy had higher mortality rates (in both Qataris and non-Qataris) (20.5% vs. 6.1%; p value<0.001 and 16.1% vs. 9.4%; p<0.001, respectively), there were no significant differences between the ethnic groups in regard to in-hospital complications. Patients treated with thrombolytic therapy had lower incidence of in-hospital complication regarding acute heart failure, post-myocardial angina, heart block and arrhythmia. Thrombolytic therapy reduced mortality rate in acute myocardial infarction by 69%. Logistic regression analysis had shown that arrhythmia, acute heart failure, heart block, cardiogenic shock, diabetes mellitus and stroke were independent predictors of increased mortality. Thrombolysis was used in 61.4%, which is still underutilized when compared to a few available studies in the Gulf area, and to other studies in the developed world. CONCLUSION: In the current study, use of thrombolysis in acute myocardial infarction was associated with significant decrease in in-hospital mortality and morbidity. Mortality rate was higher in the Qatari nationals when compared to non-Qataris. Reperfusion therapy may be underutilized in the developing world. Increased use of reperfusion therapy would result in reduced mortality rate. Global measures to encourage the use of reperfusion therapy including patients' education, and strategies to improve the health care system are needed.

Does hospitalization for congestive heart failure occur more frequently in Ramadan: a population-based study (1991-2001).

OBJECTIVE: Over one billion Muslims fast worldwide during the month of Ramadan. Fasting during Ramadan is essentially a radical change in lifestyle for the period of one lunar month, so it is important to see the response of congestive heart failure patients to this change. Our objective in this study is to investigate whether Ramadan fasting has any effect on the number of hospitalization for congestive heart failure (CHF) in a geographically defined population. METHODS: We conducted a retrospective review of clinical data study on all Qatari patients in Qatar for a period of 10 years (January 1991 through December 2001) who were hospitalized with heart failure. Patients were divided according to the time of presentation in relation to the month of Ramadan, 1 month before, during and 1 month after Ramadan. The number of hospitalization for CHF in various time periods was analyzed. The age of presentation, gender, cardiovascular risk factor profiles (smoking status, hypertension, hypercholesterolemia, diabetes, pre-existing coronary heart disease) and outcome were analyzed. RESULTS: Of the 20,856 patients treated during the 10-year period, 8446 of them were Qataris with 5095 males and 3351 females. Overall, 2160 Qatari patients were hospitalized for CHF and their mean age and standard deviation was 64.2 +/- 11.5 years, 52.4% were hypertensives, 18.5% had hypercholestrolemia, 17.7% were current smokers and 56.5% were diabetics. The overall mortality was 9.7%. The number of hospitalization for CHF was not significantly different in Ramadan (208 cases) when compared to a month before Ramadan (182 cases) and a month after Ramadan (198 cases); p > 0.37). There was no significant difference found in the baseline clinical characteristics or mortality (11.5%, 7.7% and 9.6%, respectively; p > 0.43) in patients presenting in various time periods. CONCLUSION: This population-based study demonstrates that no significant difference was found in number of hospitalization for CHF while fasting in Ramadan when compared to the non-fasting months.

The effect of hypertension as a predictor of risk for congestive heart failure patients over a 10-year period in a newly developed country.

AIMS: Cardiovascular disease is the leading cause of mortality and morbidity in the western world and has reached epidemic proportions. The incidence of congestive heart failure (CHD) and hypertension is also rising rapidly in many of the affluent Arab nations and cardiovascular diseases continue to be a leading cause of morbidity and mortality among adult Qataris and Asians residing in Qatar. OBJECTIVE: The objective of this study is to assess the effect of hypertension among patients admitted to hospital in Qatar with CHD and to identify risk factors that contribute to the development of CHD in hypertensive subjects. DESIGN: This is a retrospective cohort study. SETTING: Hamad General Hospital, Hamad Medical Corporation. SUBJECTS: All patients who were hospitalized with CHD with or without hypertension in the Hamad General Hospital, State of Qatar, from 1991 to 2001. METHODS: The diagnostic classification of definite CHD was made in accordance with criteria based on the International Classification of Disease, ninth revision (ICD-9]. RESULT: A total of 20,856 patients were treated during the 10-year period; 8446 were Qataris. Among them, 60% were males and 40% females. Among the total patients (3713) hospitalized with CHD, 1744 (46.9%) had hypertension. Furthermore, the incidence of hypertension was slightly higher in males than in females (56.4 vs 43.6%). A statistically significant difference was found between hypertensive and non-hypertensive cases with diabetes mellitus and angina. Hypertensive subjects were more likely to have diabetes (p < 0.001) and angina (p < 0.030). The mortality rate of CHD patients with hypertension was higher among Qataris than among non-Qataris (p < 0.038). CONCLUSION: Hypertension was the most common risk factor for CHD; it contributed a large proportion of heart failure cases in this population-based sample. Preventive strategies directed toward earlier detection of elevated blood pressure and its control are likely to offer the greatest promise for reducing the incidence of CHD and its associated mortality.

Primary percutaneous coronary interventions in patients with acute myocardial infarction and prior coronary artery bypass grafting.

BACKGROUND: The outcome of patients with previous coronary artery bypass grafting (CABG) undergoing primary percutaneous coronary intervention (PCI) for the treatment of acute myocardial infarction (AMI) is unclear. We sought to assess the outcome of patients with prior CABG undergoing primary PCI for the treatment of AMI. METHODS AND RESULTS: Between 1991 and 1997, 1072 patients with AMI underwent primary PCI without antecedent thrombolytic therapy at the Mayo Clinic. There were 128 patients with previous CABG and 944 without previous CABG. Patients with previous CABG were further subdivided according to the treated vessel: native vessels (n = 65) and bypass graft (n = 63). Clinical and angiographic characteristics and 30-day and 1-year outcomes were evaluated. Patients with previous CABG were significantly older and had a higher incidence of diabetes, hypertension, and hypercholesterolemia. They had a lower left ventricular ejection fraction and were also more likely to have congestive heart failure. After 1 year of follow-up, adverse cardiac events (death, MI, CABG, or repeat PCI) were significantly greater in patients with prior CABG (49.2% vs 35.9%, P =.04). With use of multivariate logistic regression analysis to adjust for differences in baseline characteristics, the treatment of vein graft was independently associated with adverse cardiac events (relative risk 1.48 [95% confidence interval 1.07-2.03], P =.02), but a history of prior CABG itself was not (relative risk 1.22 [95% confidence interval 0.96-1.56], P =.11). CONCLUSIONS: Primary PCI for AMI in patients with previous CABG is associated with higher adverse events largely attributable to adverse baseline clinical characteristics and the treatment of a vein graft.

Pathophysiology, diagnosis, and current management strategies for chest pain in patients with normal findings on angiography.

Chest pain syndromes in patients with normal angiographic findings represent a multifactorial pathophysiologic state, which may range from abnormalities in pain perception to abnormalities in endothelial- and non-endothelial-dependent coronary flow reserve associated with myocardial ischemia. Treatment begins with an accurate diagnosis by obtaining a comprehensive history and performing a physical examination, followed possibly by performing functional angiography in those who continue to have symptoms. This approach may help to determine appropriate treatment.

Obesity is independently associated with coronary endothelial dysfunction in patients with normal or mildly diseased coronary arteries.

OBJECTIVES: This study evaluates the impact of obesity on coronary endothelial function in patients with normal or mild coronary artery disease. BACKGROUND: The American Heart Association (AHA) has recently classified obesity as a modifiable risk factor for coronary heart disease. METHODS: A total of 397 consecutive patients with normal or mildly diseased coronary arteries at angiography underwent coronary vascular reactivity evaluation using intracoronary adenosine, acetylcholine and nitroglycerin. Patients were divided into three groups based on the body mass index (BMI): Group 1, patients with a BMI <25 (n = 117, normal weight); Group 2, patients with a BMI 25-30 (n = 149, overweight) and Group 3, patients with a BMI >30 (n = 131, obese). RESULTS: There were no significant differences among the groups in regard to other cardiovascular risk factors, except that overweight but not obese patients were significantly older than normal-weight patients (47 +/- 1 years in Group 1, 53 +/- 1 years in Group 2 and 50 +/- 1 years in Group 3, p < 0.001). The percent change of coronary blood flow to acetylcholine (%delta CBF Ach) was significantly lower in the obese patients than in the normal-weight group (85.2 +/- 12.0% in Group 1, 63.7 +/- 10.0% in Group 2 and 38.1 +/- 9.6% in Group 3, p = 0.009). By multivariate analysis, overweight (odds ratio, 1.55; 95% confidence interval, 1.2-2.0) and obesity (odds ratio, 2.41; 95% confidence interval, 1.5-4.0) status were independently associated with impaired coronary endothelial function. CONCLUSIONS: The study demonstrates that obesity is independently associated with coronary endothelial dysfunction in patients with normal or mildly diseased coronary arteries.

Immediate and one-year outcome in patients with coronary bifurcation lesions in the modern era (NHLBI dynamic registry).

Balloon angioplasty of bifurcation lesions has been associated with lower success and higher complication rates than most other lesion types. The development of alternative strategies such as debulking and stenting, either alone or in combination, are currently used relatively often. The relative role of these newer approaches in improving acute or long-term outcome, however, remains uncertain. Of the total of 2,436 patients treated between July 1997 to February 1998 in the National Heart, Lung, and Blood Institute Dynamic Registry, there were 321 patients (group 1) with bifurcation lesions and 2,115 patients without any bifurcation lesions attempted (group 2). Treatment strategies in terms of major devices used were significantly different between the 2 groups (group 1 vs 2): balloon angioplasty alone (23.1% vs 26.5%), balloon angioplasty and rotational atherectomy (6.9% vs 4.4%), balloon angioplasty and stent (55.8% vs 59.9%), and balloon angioplasty, rotational atherectomy, and stent (10.3% vs 7%) with p <0.01. There were no significant differences between the groups in terms of age, gender, and frequency of prior myocardial infarction (MI) or coronary artery bypass graft surgery (CABG). Complete angiographic success was achieved in only 86% of bifurcation lesions versus 93.5% of nonbifurcation lesions (p <0.001). In-hospital complication rates were increased in patients with bifurcation lesions compared with the nonbifurcation group: MI, 3.7% versus 2.6%; CABG, 2.2% versus 1.1%; side branch occlusion, 7.3% versus 2.3% (p <0.001); and the composite of death, MI, and any CABG, 7.2% versus 5.0%. At 1-year follow-up, major adverse cardiac events were 25% higher in group 1 than in group 2 (32.1% vs 25.7%, p <0.05). We conclude that despite the widespread use of newer percutaneous devices, treatment of bifurcation lesions remains difficult and is associated with decreased success and increased complication rates compared with nonbifurcation lesions.

Comparison of immediate and one-year outcome after coronary angioplasty of narrowing < 3 mm with those > or =3 mm ( the National Heart, Lung, and Blood Institute Dynamic Registry).

Balloon angioplasty of small coronary artery lesions has been associated with lower success and higher complication rates than large coronary artery lesions. This study evaluates the in-hospital and 1-year outcome of the treatment of small coronary artery lesions in the modern era of interventional cardiology and compares it with the outcome of treating large coronary artery lesions. Of 1,658 patients with a single lesion treated from July 1997 to February 1998 in the National Heart, Lung, and Blood Institute (NHLBI) Dynamic Registry, there were 587 patients with small coronary artery lesions (<3 mm) and 1,071 patients with large coronary artery lesions (> or =3 mm). Success, in-hospital, and 1-year outcomes between both groups were compared. Patients with lesions in small coronary arteries were more often women, insulin-treated diabetics, and had undergone more prior coronary bypass graft surgery. Conventional angioplasty alone was performed more often and angioplasty with stents was performed less often in the small coronary artery than in the large coronary artery group. Angiographic success was slightly lower in the small coronary artery group (94.2% vs 96.9%, p <0.05). Periprocedural and in-hospital complication rates were similar in both groups. Likewise, at 1-year follow-up, major adverse cardiac events including death, myocardial infarction, and coronary artery bypass graft surgery were relatively low and comparable between the 2 groups, although patients with small coronary arteries were more likely to undergo repeat revascularization (17.4% vs 13.6%, p <0.05). Treatment of lesions in small coronary arteries in the modern era is associated with high success and low complication rates, comparable to the treatment of large coronary artery lesions, although the incidence of repeat revascularization was significantly greater at follow-up even if stents were used.

Syndrome X.

Syndrome X, defined as typical angina with positive exercise test results and normal coronary angiographic findings, represents a multifactorial pathophysiologic state that may range from abnormalities in pain perception to abnormalities in endothelial- and nonendothelial-dependent coronary flow reserve associated with myocardial ischemia. Treatment begins with accurate diagnosis by means of a comprehensive coronary vascular reactivity evaluation. This may lay the groundwork for appropriate treatment. The management of patients with syndrome X is challenging, and it may be necessary to attempt various medications depending on the patient's response. We feel that the first step in the treatment is accurate diagnosis. This is done by performing a functional angiogram (assessment of endothelial-dependent and endothelial-independent coronary flow reserve). In those without evidence of coronary flow reserve abnormalities, reassurance might be curative; however, in those who continue to have symptoms, a trial of imipramine therapy at a dose of 50 mg/d may be attempted, provided other organic disorders (in particular gastrointestinal disorders) are excluded. Those who demonstrate evidence of abnormal coronary vascular reactivity are approached as outlined in Figure 1. Patients are advised to avoid medications that may cause coronary "spasm." We routinely refer our patients to the cardiovascular health clinic for risk factor management and an exercise program. Our first choice of medications usually consists of slow-release calcium channel blockers. We tend to start with a once-a-day regimen, and based on the response, we occasionally change the regimen to twice a day. If the functional angiogram reveals concomitant epicardial disease, then nitrates are added to the medical regimen. Angiotensin-converting enzyme inhibitors are part of the treatment if the patient has hypertension or diabetes or if calcium channel blocker therapy fails. l-Arginine at an initial dosage of 1 g three times daily is added and may be increased to 3 g three times daily if no contraindications are present. Because there are no data regarding the effect of l-arginine, which may affect insulin secretion, in patients with diabetes, we use caution in this patient population. There is no "gold standard" therapy for syndrome X, so each patient may respond differently to the initial medical therapy. Thus, we follow these patients closely to monitor their response to treatment.