Maria Khan

Stroke in Asia: geographical variations and temporal trends

Asian countries are in various stages of epidemiological transition and therefore exhibit a great diversity in disease patterns. Collectively, they comprise almost two-third of the worlds total mortality due to stroke. The purpose of this review is to explore existing epidemiological data on stroke, highlight the temporal trends in stroke epidemiology in various regions of Asia and predict future patterns based on these observations. Our search revealed that there is a lack of good epidemiological data from most Asian countries. Whatever data exist are not comparable due to lack of standardised methodology for ascertaining stroke and its subtypes. For this and other reasons, these estimates exhibit country-to-country variation and also within-country variability. We have also reviewed temporal trends in stroke incidence and prevalence in 12 Asian countries and the evolution of stroke subtypes over the past two decades. Important observations include a rise in stroke incidence in most Asian countries, an earlier age at onset compared with the West, a relative increase in the proportion of ischaemic strokes and a decline in haemorrhagic strokes. Among ischaemic stroke subtypes, lacunar strokes, which were once the commonest variety, are now declining. Emerging data suggest that large artery atherosclerosis and in particular that of intracranial vessels is the predominant aetiology in most Asian countries. The review also identified important gender differences in terms of stroke risk factors, prevalence and outcomes. There is need for sound epidemiological data from most countries to understand the disease better and plan policy-level interventions to decrease the burden. We identify a need for standard format or guidelines for conducting stroke epidemiological studies especially in developing Asian countries. This region must be identified as a priority region for stroke-related interventions and preventive strategies by global healthcare authorities and organisations.

Haemorrhagic strokes in pregnancy and puerperium

There is an increased risk of strokes in pregnancy and puerperium. Intracranial haemorrhage is the rarer of the two stroke subtypes but carries a greater morbidity and mortality for both the mother and the child. This review highlights the causes of pregnancy-related intracranial haemorrhage and its management. The incidence varies from region to region with the highest being reported from China and Taiwan. Majority of these haemorrhages are secondary to hypertensive disorders of pregnancy with smaller proportions related to aneurysm and arteriovenous malformation rupture. A small but important contributor is cortical venous thrombosis which, although predominantly gives rise to ischaemic lesions, may lead to parenchymal haemorrhages as well. Presentation is usually with headaches or seizures, with or without focal deficits. Diagnosis requires brain imaging with computerized tomography or magnetic resonance imaging, and the necessity of investigation when this diagnosis is suspected supersedes the small risk of fetal malformation. Management follows the general management principles for intracranial haemorrhage management. Blood pressures need to be strictly monitored and medicines used for controlling them may differ slightly due to teratogenic effects. For preeclampsia, early but safe delivery is the best treatment. For cortical venous thrombosis, low-molecular-weight heparin is the preferred agent. Aneurysms and vascular malformations need to be definitively treated to prevent re-bleed and this can be achieved through surgical or endovascular procedures. The timing of surgery depends on neurosurgical considerations. However, the timing and mode of delivery are governed by obstetric factors. Risk of future haemorrhage depends on whether the underlying aetiology can be and has been definitively treated.

Functional, cognitive and psychological outcomes, and recurrent vascular events in Pakistani stroke survivors: a cross sectional study

BackgroundThere is little direct data describing the outcomes and recurrent vascular morbidity and mortality of stroke survivors from low and middle income countries like Pakistan. This study describes functional, cognitive and vascular morbidity and mortality of Pakistani stroke survivors discharged from a dedicated stroke center within a nonprofit tertiary care hospital based in a multiethnic city with a population of more than 20 million.MethodsPatients with stroke, aged > 18 years, discharged alive from a tertiary care centre were contacted via telephone and a cross sectional study was conducted. All the discharges were contacted. Patients or their legal surrogate were interviewed regarding functional, cognitive and psychological outcomes and recurrent vascular events using standardized, pretested and translated scales. A verbal autopsy was carried out for patients who had died after discharge. Stroke subtype and risk factors data was collected from the medical records. Subdural hemorrhages, traumatic ICH, subarachnoid hemorrhage, iatrogenic stroke within hospital and all other diagnoses that presented like stroke but were subsequently found not to have stroke were also excluded. Composites were created for functional outcome variable and depression. Data were analyzed using logistic regression.Results309 subjects were interviewed at a median of 5.5 months post discharge. 12.3% of the patients had died, mostly from recurrent vascular events or stroke complications. Poor functional outcome defined as Modified Rankin Score (mRS) of > 2 and a Barthel Index (BI) score of < 90 was seen in 51%. Older age (Adj-OR-2.1, p = 0.01), moderate to severe dementia (Adj-OR-19.1, p < 0.001), Diabetes (Adj-OR-2.1, p = 0.02) and multiple post stroke complications (Adj-OR-3.6, p = 0.02) were independent predictors of poor functional outcome. Cognitive outcomes were poor in 42% and predictors of moderate to severe dementia were depression (Adj-OR-6.86, p < 0.001), multiple post stroke complications (Adj-OR-4.58, p = 0.01), presence of bed sores (Adj-OR-17.13, p = 0.01) and history of atrial fibrillation (Adj-OR-5.12, p < 0.001).ConclusionsPakistani stroke survivors have poor outcomes in the community, mostly from preventable complications. Despite advanced disability, the principal caretakers were family rarely supported by health care personnel, highlighting the need to develop robust home care support for caregivers in these challenging resource poor settings.

Growing burden of stroke in Pakistan: a review of progress and limitations

Stroke rates in middle-aged people are five to ten times higher in Pakistan, India, Russia, China, and Brazil, compared with the United Kingdom or United States. South Asia is home to 20% of the worlds population and has one of the highest burdens of cardiovascular disease in the world. With an aging population, there is an expected increase in the number of stroke cases and a corresponding increase in the burden of stroke in developing countries including South Asian countries like Pakistan. Limited data from prior studies in developing countries indicate that stroke epidemiology differs between these and Western countries. These differences include a higher incidence of stroke at younger ages, a higher prevalence of hemorrhagic stroke, and higher age-specific prevalence rates of stroke in women. The reasons for these differences in stroke epidemiology in developing countries are not clear. This may be explained by higher prevalence of established stroke risk factors, or potential nontraditional risk factors such as water pipe smoking, use of daldaghee or naswaar, and paan chewing; hepatitis and rheumatic heart disease may also contribute to these differences. Acute and long-term stroke treatment has shown limited progress in Pakistan like other developing countries because of poor awareness of patients and general physician on stroke symptomatology, management of stroke risk factors, lack of specialized stroke units in the country, very low utilization of thrombolytic therapy because of financial constraints and, above all, poor knowledge of physicians on the role of rehabilitation and its different aspects in the management of post stroke disability.

Pregnancy and Puerperium-Related Strokes in Asian Women

BACKGROUNDnDespite an increased risk of stroke in pregnancy and puerperium, the overall incidence of the condition in this population is low. Therefore, there is limited data pertaining to these patients particularly from Asian countries. Our objective was to describe the risk factors and outcomes of 110 pregnancy-related ischemic strokes from 5 Asian countries.nnnMETHODSnData were collected by retrospective chart review in most cases and prospectively in the rest. Inclusion criteria for this subanalysis were women, pregnant or within 1-month postpartum, presenting to the study center with acute ischemic stroke (arterial or venous) confirmed by neuroimaging. Intracranial hemorrhages other than the ones associated with cerebral venous thrombosis or hemorrhagic infarct were excluded. Risk factors were diagnosed based on already published criteria. Outcomes were measured using modified Rankin score. Statistical analysis was done using Statistical Package for Social Sciences version 19.0.nnnRESULTSnIn all, 110 women with mean age of 27.94 years presented with pregnancy-related ischemic strokes; 58.2% of the strokes occurred postpartum and 49.1% were secondary to cerebral venous thrombosis. Venous strokes were significantly more likely to occur postpartum compared with arterial strokes (P=.01), to have abnormal hypercoagulable panel result on admission (P<.001), less likely to have traditional stroke risk factors (P<.001), to have hemorrhagic conversion of stroke (P<.001), and to have lesser stroke severity and better functional outcome at 3 months (P<.001 for each).nnnCONCLUSIONnCerebral venous thrombosis is a significant contributor to pregnancy-related strokes in Asian women. Both traditional and pregnancy-specific risk factors should be addressed to control ischemic stroke risk in these women.

Ischemic Strokes in Pakistan: Observations from the National Acute Ischemic Stroke Database

BACKGROUNDnThe objective of this study was to establish a multicenter ischemic stroke registry, first of its kind in Pakistan, to provide insight into the epidemiology, subtypes, and risk factors of ischemic strokes in this country.nnnMETHODSnFour academic centers (3 urban and 1 rural) participated in this project. The inclusion criteria for subjects included adults (>14 years) with acute neurologic deficit, consistent with clinical diagnosis of ischemic stroke and supported by neuroimaging.nnnRESULTSnData were available for 874 subjects. Mean age of the subjects was 59.7 years, 60.5% were males, and 18% were young. Large vessel strokes were the most common subtype found in 31.7% subjects, followed by small vessel disease (25.7%) and cardioembolic strokes (10.4%). Almost 32% subjects had ill-defined etiology for their ischemic stroke. Dyslipidemia was a most common risk factor present in 83% patients. Data related to in-hospital complications were available for 808 subjects, of which 233 complications were recorded. Pneumonia was the most common of these seen in 105 (13%) subjects, followed by urinary tract infection (7.2%). Outcome at discharge was recorded for 697 subjects. Ninety-two had died during their hospital stay (13.2%). Only 36% subjects had a favorable outcome at discharge defined as a modified Rankin Scale (mRS) score of 2 or less. A total of 446 of 697 subjects had poor outcome at discharge (defined as an mRS score≥3).nnnCONCLUSIONSnHypertension and dyslipidemia were the most common risk factors and large vessel atherosclerosis was the most common stroke etiology. Elderly patients were significantly more likely to have in-hospital complications, die during their hospital stay, and have a higher mRS score at discharge.

Left atrial volumes and associated stroke subtypes

BackgroundCardio embolism and cerebrovascular atherosclerosis are two major mechanisms of stroke. Studies investigating associations between advanced echocardiographic parameters and stroke mechanisms are limited.MethodsThis study is a standardized review of 633 patients admitted to the stroke service of a tertiary care hospital following a standardized stroke investigation and management pathway. Stroke subtypes were characterized using the Causative Classification System, using the hospitals online radiologic archival system with CCS certified stroke investigators. Patients with two mechanisms were excluded.ResultsPatients with cardioembolic stroke had a higher proportion of atrial fibrillation (pu2009<u20090.001), acute myocardial infarction (pu2009<u20090.001) and ischemic heart disease (pu2009<u20090.001). On electrocardiogram (ECG) and transthoracic Echo (TTE), patients with cardioembolic stroke had a greater atrial fibrillation (pu2009<u2009.00), left ventricular thrombus (pu2009<u2009.00), left ventricular ejection fraction <30% (pu2009<u2009.00) and global hypokinesia (pu2009<u2009.00) Patients with cardioembolic stroke had higher mean left atrial volume indices (LAVi) (pu2009<u20090.001), mean left ventricular mass indices (LVMi) (pu2009<u20090.05) and mean left atrial diameters (LAD) (pu2009<u20090.05). At LAVi of 29–33xa0ml/m2, the risk of atherothrombotic stroke increased. The risk of cardioembolic stroke increased with LAVi of 34xa0ml/m2 and above.ConclusionLeft atrial volume indices may be linked to specific stroke phenotype. At mild increases in left atrial dimensions, the risks of atherosclerotic stroke are high, and probably reflect hypertension as the unifying mechanism. Further increases in left atrial dimensions shifts the risk towards cardioembolic stroke.

Risk factor profiles of South Asians with cerebrovascular disease

Background There is a paucity of population based data about the coexistent proportions of risk factors for stroke in South Asians. Methods In this cross sectional survey performed in an urban slum, individuals 35 years of age or older were invited for participation through a simple random sample drawn from baseline census data. For each participant a systematic history and examination was performed to confirm the following risk factors: diabetes, hypertension, obesity, tobacco use, coronary artery disease, family history of coronary artery disease and/or stroke. Cerebrovascular events (stroke and TIA) were verified by a vascular neurologist. We report the association of risk factor groups and the presence of contemporaneous cerebrovascular event. Results Five hundred and forty-five individuals (49.4% females) participated in the study. One hundred and nineteen (21.8%) individuals had a cerebrovascular event (stroke and / or TIA). Obesity was found to be the predominant risk factor, occurring in 310 individuals (56.9%), followed by total hypertension (284; 52.1 %) and tobacco use respectively (213; 39 %). Cerebrovascular event increased in percentage with quantitative increase in risk factors. Cerebrovascular event prevalence was 14.3% with one risk factor, 22% with two, 27% with three, 33% with four, and 86% with five risk factors respectively. The combination of 4 risk factors (hypertension, diabetes, obesity and cigarette smoking) conferred the highest odds of having cerebrovascular event at 4.9 (P 0.03). Conclusion South Asians in an urban slum often have multiple modifiable risk factors for cerebrovascular event, increasing numbers of risk factors increase the risk of stroke and TIA.

Stroke knowledge and screening in a high prevalence, low‐income community

The burden of stroke is rising in lowto middle-income countries (LMIC) (1). These countries, however, do not possess the resources for this transition from communicable diseases to a greater proportion of chronic disease. With this in mind, we performed a study in a peri-urban slum in Karachi, Pakistan, to validate a stroke symptom questionnaire that can be used by community workers to identify communitydwelling stroke patients. We also assessed participants’ knowledge regarding stroke symptoms and risk factors. Two community workers interviewed 322 participants after receiving initial training. The sensitivity and specificity of the questionnaire for detecting stroke was 77·1% (CI: 64·1%–86·9%) and 85·8% (CI: 83·5%–87·5%). Hemianesthesia (72·9%) and hemiplegia (64·6%) were the most sensitive symptoms. The overall knowledge of participants was poor (Table 1) with an average of 2·9 correct responses per participant. One hundred eighty-two participants (59·2%) failed to answer any question correctly. Around 25% identified stroke as a preventable condition. Only 13% to 15% subjects identified hypertension, diabetes and tobacco as risk factors for stroke despite the self-reported prevalence of the conditions being 60%, 12% and 80% respectively. Our study identifies a pragmatic and cost-effective tool that can be useful in communities that lack health-care infrastructure. It allows task shifting of screening stroke patients in the community to community workers who demonstrated high acceptability rates. Our study also shows the need to improve the knowledge regarding stroke risk factors and management in the community that seems to resort to indifference in the face of what they consider inevitable fate.

Population attributable risks of stroke from intracranial atherosclerotic disease (ICAD) in South Asian Pakistanis

Stroke from intracranial atherosclerotic disease, ICAD, is numerically the most common cause of stroke in the world. The brunt of ICAD is borne by emerging populations in lowand middle-income countries. Currently, control of risk factors is the best intervention for ICAD, which has one of the highest rates of recurrence among ischemic stroke sub-types. We report the population attributable risks (PARs) of ICAD strokes in Pakistani South Asians. PARs were calculated using 314 cases with ICAD and 331 controls from a hospital-based age, gender, matched case-control study (1). The factors that were independently associated with ICAD stroke in this case control study were hypertension [odds ratio (OR): 3·33; confidence interval (CI): 2·31–4·78], Diabetes mellitus (DM) (OR: 2·29; CI: 1·56–3·35), unemployment (OR: 2·15; CI: 1·21–3·83), low income (OR: 1·59; CI: 1·01–2·51), and chronic stress (OR: 3·67; CI: 2·13–6·34) (2). The PARs for the development of ICAD stroke were as follows: history of hypertension 48·7%, unemployment 23·8%, history of diabetes10·7%, family history of stroke 10·7 %, income 10·5%, and moderate to severe chronic stress 3·1%. Taking the lifetime prevalence of stroke as 20% from a reported study and the population of Pakistan as 187 million people, the projected number of stroke patients is 40 million (3). As per this study, ICAD contributes to 20% of all strokes. Based on this the projected estimation, population due to ICAD stroke is around 8 000 000 million in Pakistan. These risk factors explain the ICAD stroke in 774 400 patients (Table 1). Although there is increasing appreciation of the public health threat of noncommunicable diseases, there has been little in the way of policy efforts at population control. Studies show that this could be achieved by a combination of lay worker focus on lifestyle change and training the frontline providers with continuous medical education to affect adherence to evidence-based interventions (4). Additionally, we consider mental health intervention an important part of any holistic strategy to impact stroke prevention; solutions are possible (5). Lastly, effective social interventions in terms of employment and income may contribute significantly to the prevention of stroke from ICAD. These PARs can be used to plan longitudinal population implementation studies for impact. They offer insight into the potential impact of interventions for the most common form of ischemic stroke relevant to developing countries.