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Evaluation of the consequences associated with diffuse vascular disease history in patients diagnosed with peripheral arterial disease: estimates from Saskatchewan health data
Background:
Peripheral arterial disease (PAD) is caused by narrowing of the arteries in the lower extremities. Limited data exist concerning the impact of diffuse vascular disease (DVD) on prognosis and costs. Thus, the objective of this study is to estimate the impact of DVD on morbidity, mortality and costs.MethodS PAD was identified between 1985 and 1995 and classified by extent of DVD at diagnosis: none (PAD only, reference group), prior myocardial infarction (MI), prior stroke, prior MI and stroke (MI+stroke), prior transient ischemic attack (TIA). Deaths and hospitalizations were identified through December 2000. Hospitalization costs were estimated from the Ontario Case Cost Project, reported in 2002 $CAD. Proportional hazards analyses measured the impact of vascular involvement on mortality while controlling for risk factors (e.g., age, cardiovascular history).
Results:
Overall, 16,439 patients with PAD were included; 14.8% had a prior MI, 10.2% a prior stroke, 2.6% prior MI+stroke, 6.4% prior TIA, two-thirds had PAD only. Median survival was shorter for patients with prior MI (9.3 yrs), TIA (6.3), stroke (4.7), and MI+stroke (4.1) versus the reference group (9.9, p<0.05, all comparisons). Analyses revealed that the death risk was 60% higher in patients with prior stroke and 84% higher for MI+stroke. Atherothrombotic and bleeding event-related costs were $712, $337, $268, and $170 higher per patient/year of follow-up in patients with a history of MI+stroke, MI, stroke, and TIA, respectively.
Conclusion:
Patients diagnosed with PAD with DVD have higher risk of poor outcomes and increased costs.
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Increased susceptibility to cardiovascular effects of dihydrocapcaicin in resuscitated rats
Background:
Survivors of a cardiac arrest often have persistent cardiovascular derangements following cardiopulmonary resuscitation including decreased cardiac output, arrhythmias and morphological myocardial damage. These cardiovascular derangements may lead to an increased susceptibility towards the external and internal environment of the cardiovascular system as compared to the healthy situation. Methods: Here we tested the hypothesis that the cardiovascular system in healthy rats and rats resuscitated from a cardiac arrest may be differentially affected by a transient receptor potential vanilloid type 1 agonist, by continuous intravenous infusion of dihydrocapsaicin (DHC). Results: Compared to baseline, infusion of DHC caused an initial increase in mean arterial blood pressure in both healthy and resuscitated rats of 25% and 10%, respectively. Also, we observed an initial response of tachycardia in both healthy and resuscitated rats of 30% and 20%, respectively. Then, at high levels of DHC infusion (> 2.0 mg/kg/hr) we observed two single episodes of transient bradycardia and hypotension in 33% of the healthy rats, which was consistent with a TRPV1 agonist induced Bezold-Jarisch reflex. In contrast, in resuscitated rats we observed multiple episodes of bradycardia/hypotension in 100% of the rats and at a dose of DHC of 0.65 mg/kg/hr. Notably, this DHC effect could be completely blocked in the resuscitated rats by pre-treatment with atropine, a muscarinic acetylcholine antagonist. Conclusions: Our results indicate that the susceptibility of the rats towards TRPV1 agonist induced Bezold-Jarisch reflex is increased in those resuscitated from cardiac arrest compared to the healthy situation.
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Ethnic and sex differences in the incidence of hospitalized acute myocardial infarction: British Columbia, Canada 1995-2002
Background:
As populations in Western countries continue to change in their ethnic composition, there is a need for regular surveillance of diseases that have previously shown some health disparities. Earlier data have already demonstrated high rates of cardiovascular mortality among South Asians and relatively lower rates among people of Chinese descent. The aim of this study was to describe the differences in the incidence of hospitalized acute myocardial infarction (AMI) among the three largest ethnic groups in British Columbia (BC), Canada.
Methods:
Using hospital administrative data, we identified all patients with incident AMI in BC between April 1, 1995, and March 31, 2002. Census data from 2001 provided the denominator for the entire BC population. Ethnicity was determined using validated surname analysis and applied to the census and hospital administrative datasets. Direct age standardization was used to compare incidence rates.
Results:
A total of 34,848 AMI cases were identified. Among men, South Asians had the highest age standardized rate of AMI hospitalization at 4.97/1000 population/year, followed by Whites at 3.29, and then Chinese at 0.98. Young South Asian men, in particular, showed incidence rates that were double that of young Whites and ten times that of young Chinese men. South Asian women also had the highest age-standardized rate of AMI hospitalization at 2.35/1000 population/year, followed by White women (1.53) and Chinese women (0.49).
Conclusions:
South Asians continue to have a higher incidence of hospitalized AMI while incidence rates among Chinese remain low. Ethnic differences are most notable among younger men.
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Protocol for Past BP: a randomised controlled trial of different blood pressure targets for people with a history of stroke of transient ischaemic attack (TIA) in primary care.
Background:
Blood pressure (BP) lowering in people who have had a stroke or transient ischaemic attack (TIA) leads to reduced risk of further stroke. However, it is not clear what the target BP should be, since intensification of therapy may lead to additional adverse effects. PAST BP will determine whether more intensive BP targets can be achieved in a primary care setting, and whether more intensive therapy is associated with adverse effects on quality of life.Methods/DesignThis is a randomised controlled trial (RCT) in patients with a past history of stroke or TIA. Patients will be randomised to two groups and will either have their blood pressure (BP) lowered intensively to a target of 130 mmHg systolic, (or by 10 mmHg if the baseline systolic pressure is between 125 and 140 mmHg) compared to a standard group where the BP will be reduced to a target of 140 mmHg systolic. Patients will be managed by their practice at 1-3 month intervals depending on level of BP and followed-up by the research team at six monthly intervals for 12 months.610 patients will be recruited from approximately 50 general practices. The following exclusion criteria will be applied: systolic BP <125 mmHg at baseline, 3 or more anti-hypertensive agents, orthostatic hypotension, diabetes mellitus with microalbuminuria or other condition requiring a lower treatment target or terminal illness.The primary outcome will be change in systolic BP over twelve months. Secondary outcomes include quality of life, adverse events and cardiovascular events.In-depth interviews with 30 patients and 20 health care practitioners will be undertaken to investigate patient and healthcare professionals understanding and views of BP management.DiscussionThe results of this trial will inform whether intensive blood pressure targets can be achieved in people who have had a stroke or TIA in primary care, and help determine whether or not further research is required before recommending such targets for this population.Trial RegistrationISRCTN29062286
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Continued breathing followed by gasping or apnea in a swine model of ventricular fibrillation cardiac arrest
Background:
Continued breathing following ventricular fibrillation has here-to-fore not been described.
Methods:
We analyzed the spontaneous ventilatory activity during the first several minutes of ventricular fibrillation (VF) in our isoflurane anesthesized swine model of out-of-hospital cardiac arrest. The frequency and type of ventilatory activity was monitored by pneumotachometer and main stream infrared capnometer and analyzed in 61 swine during the first 3 to 6 minutes of untreated VF.
Results:
During the first minute of VF, the air flow pattern in all 61 swine was similar to those recorded during regular spontaneous breathing during anesthesia and was clearly different from the patterns of gasping. The average rate of continued breathing during the first minute of untreated VF was 10 breaths per minute. During the second minute of untreated VF, spontaneous breathing activity either stopped or became typical of gasping. During minutes 2 to 5 of untreated VF, most animals exhibited very slow spontaneous ventilatory activity with a pattern typical of gasping; and the pattern of gasping was crescendo-decrescendo, as has been previously reported. In the absence of therapy, all ventilatory activity stopped 6 minutes after VF cardiac arrest.
Conclusion:
In our swine model of VF cardiac arrest, we documented that normal breathing continued for the first minute following cardiac arrest.
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Prevalence of peripheral arterial disease in patients at non-high cardiovascular risk. Rationale and design of the PANDORA study
Background:
Lower extremity peripheral arterial disease (PAD) is a marker of widespread atherosclerosis. Individuals with PAD, most of whom do not show typical PAD symptoms ('asymptomatic' patients), are at increased risk of cardiovascular ischaemic events. American College of Cardiology/American Heart Association guidelines recommend that individuals with asymptomatic lower extremity PAD should be identified by measurement of ankle-brachial index (ABI). However, despite its associated risk, PAD remains under-recognised by clinicians and the general population and office-based ABI detection is still poorly-known and under-used in clinical practice. The Prevalence of peripheral Arterial disease in patients with a non-high cardiovascular disease risk, with No overt vascular Diseases nOR diAbetes mellitus (PANDORA) study has a primary aim of assessing the prevalence of lower extremity PAD through ABI measurement, in patients at non-high cardiovascular risk, with no overt cardiovascular diseases (including symptomatic PAD), or diabetes mellitus. Secondary objectives include documenting the prevalence and treatment of cardiovascular risk factors and the characteristics of both patients and physicians as possible determinants for PAD under-diagnosis.Methods/DesignPANDORA is a non-interventional, cross-sectional, pan-European study. It includes approximately 1,000 primary care participating sites, across six European countries (Belgium, France, Greece, Italy, The Netherlands, Switzerland). Investigator and patient questionnaires will be used to collect both right and left ABI values at rest, presence of cardiovascular disease risk factors, current pharmacological treatment, and determinants for PAD under-diagnosis.DiscussionThe PANDORA study will provide important data to estimate the prevalence of asymptomatic PAD in a population otherwise classified at low or intermediate risk on the basis of current risk scores in a primary care setting.Trial registration numberClinical Trials.gov Identifier: NCT00689377.
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Sex differences in the combined effect of chronic stress with impaired vascular endothelium functioning and the development of early atherosclerosis: The Cardiovascular Risk in Young Finns study
Background:
The syndrome of vital exhaustion (VE), characterized by fatigue and irritability, may contribute to an increased risk of atherosclerosis. The aim of the study was to explore sex differences in the interactions of VE with endothelial dysfunction and VE with reduced carotid elasticity, the important contributors to the development of early atherosclerosis, on preclinical atherosclerosis.
Methods:
The participants were 1002 women and 719 men aged 24-39 examined in the Cardiovascular Risk in Young Finns study. Vital exhaustion was measured using the Maastricht Questionnaire. Preclinical atherosclerosis was assessed by carotid intima-media thickness (IMT), endothelial function was measured by brachial flow-mediated dilatation (FMD), and arterial elasticity by carotid artery compliance (CAC) using ultrasound techniques.
Results:
We found a significant CAC x VE interaction for IMT only for the men. Our results imply that high VE level significantly related to high IMT levels among the men with low CAC, but not among the women with low CAC or among the women or men with high CAC. No significant FMD x VE interactions for IMT for the women or men were found.
Conclusions:
High VE may exert an effect on IMT for men with impaired arterial elasticity. The results suggest that high vitally exhausted men with reduced arterial elasticity are at increased risk of atherosclerosis in early life and imply men's decreased stress coping in relation to stressful psychological coronary risk factors.
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Moxibustion for hypertension: a systematic review
Background:
Moxibustion is a traditional East Asian medical therapy that uses the heat generated by burning herbal preparations containing Artemisia vulgaris to stimulate acupuncture points. The aim of this review was to evaluate previously published clinical evidence for the use of moxibustion as a treatment for hypertension.
Methods:
We searched 15 databases without language restrictions from their respective dates of inception until March 2010. We included randomized controlled trials (RCTs) comparing moxibustion to either antihypertensive drugs or no treatment. The risk of bias was assessed for each RCT.
Results:
During the course of our search, we identified 519 relevant articles. A total of 4 RCTs met all the inclusion criteria, two of which failed to report favorable effects of moxibustion on blood pressure (BP) compared to the control (antihypertensive drug treatment alone). However, a third RCT showed significant effects of moxibustion as an adjunct treatment to antihypertensive drug therapy for lowering BP compared to antihypertensive drug therapy alone. The fourth RCT included in this review addressed the immediate BP-lowering effects of moxibustion compared to no treatment. None of the included RCTs reported the sequence generation, allocation concealment and evaluator blinding.
Conclusion:
There is insufficient evidence to suggest that moxibustion is an effective treatment for hypertension. Rigorously designed trials are warranted to answer the many remaining questions.
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Ventricular-arterial uncoupling in heart failure with preserved ejection fraction after myocardial infarction in dogs - invasive versus echocardiographic evaluation.
Background:
Heart failure with preserved left ventricular ejection fraction and abnormal diastolic function is commonly observed after recovery from an acute myocardial infarction. The aim of this study was to investigate the physiopathology of heart failure with preserved ejection fraction in a model of healed myocardial infarction in dogs.
Methods:
Echocardiography, levels of neurohormones and conductance catheter measurements of left ventricular pressure-volume relationships were obtained in 17 beagle dogs 2 months after a coronary artery ligation, and in 6 controls.
Results:
Healed myocardial infarction was associated with preserved echocardiographic left ventricular ejection fraction (0.57 ± 0.01, mean ± SEM) and altered Doppler mitral indices of diastolic function. NT-proBNP was increased, aldosterone was decreased, and norepinephrine was unchanged. Invasive measurements showed a markedly decreased end-systolic elastance (2.1 ± 0.2 vs 6.1 ± 0.8, mmHg/ml, p < 0.001) and end-systolic elastance to effective arterial elastance ratio (0.6 ± 0.1 vs 1.4 ± 0.2, p < 0.001), with altered active relaxation (dP/dtmin -1992 ± 71 vs -2821 ± 305, mmHg/s, p < 0.01) but preserved left ventricular capacitance (70 ± 6 vs 61 ± 3, ml at 20 mmHg, p = NS) and stiffness constant. Among echocardiographic variables, the wall motion score index was the most reliable indicator of cardiac contractility while E', E/A and E'/A' were correlated to dP/dtmin.
Conclusions:
In the canine model of healed myocardial infarction induced by coronary ligation, heart failure is essentially characterized by an altered contractility with left ventricular-arterial uncoupling despite vascular compensation rather than by abnormal diastolic function
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In-hospital complications after invasive strategy for the management of Non STEMI: women fare as well as men
Background:
To analyze the in-hospital complication rate in women suffering from non-ST elevation myocardial infarction treated with percutaneous coronary intervention (PCI) compared to men.
Methods:
The files of 479 consecutive patients (133 women and 346 men) suffering from a Non STEMI (Non ST-segment elevation myocardial infarction) between the January 1st 2006 and March 21st 2009 were retrospectively analyzed with special attention to every single complication occurring during hospital stay. Data were analyzed using nonparametric tests and are reported as median unless otherwise specified. A p value < .05 was considered significant.
Results:
As compared to men, women were significantly older (75.8 vs. 65.2 years; p < .005). All cardiovascular risk factors but tobacco and hypertension were similar between the groups: men were noticeably more often smoker (p < .0001) and women more hypertensive (p < .005). No difference was noticed for pre-hospital cardiovascular drug treatment. However women were slightly more severe at entry (more Killip class IV; p = .0023; higher GRACE score for in-hospital death - p = .008 and CRUSADE score for bleeding - p < .0001). All the patients underwent PCI of the infarct-related artery after 24 or 48 hrs post admission without sex-related difference either for timing of PCI or primary success rate. During hospitalization, 130 complications were recorded. Though the event rate was slightly higher in women (30% vs. 26% - p = NS), no single event was significantly gender related. The logistic regression identified age and CRP concentration as the only predictive variables in the whole group. After splitting for genders, these parameters were still predictive of events in men. In women however, CRP was the only one with a borderline p value.
Conclusions:
Our study does not support any gender difference for in-hospital adverse events in patients treated invasively for an acute coronary syndrome without ST-segment elevation and elevated troponin.
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