Transcatheter aortic valve implantation (TAVI) has emerged as an important treatment for patients with severe symptomatic aortic stenosis who are at high operative risk, but accurate estimates of ...serious adverse effects in contemporary practice are not available.
To quantify the adverse effects associated with TAVI, and to evaluate whether the type of transcatheter valve and the route of valve implantation are associated with differences in adverse outcomes.
PubMed to 5 May 2012.
All studies that included at least 100 patients who had TAVI and reported at least 1 outcome of interest.
Two reviewers abstracted the data independently. A random-effects model was used to combine data on adverse outcomes and conduct stratified analyses.
A total of 49 studies enrolling 16 063 patients met the inclusion criteria. Overall 30-day and 1-year survival after TAVI were 91.9% (95% CI, 91.1% to 92.8%) and 79.2% (CI, 76.9% to 81.4%), respectively. Heart block requiring permanent pacemaker implantation was the most common adverse outcome (13.1%) and was 5 times more common with the CoreValve (Medtronic, Minneapolis, Minnesota) than the Sapien valve (Edwards Lifesciences, Irving, California) implanted using the transarterial route (25.2% vs. 5.0%, respectively). The overall rate of vascular complications was 10.4% and was highest with transarterial implantation of the Sapien valve (22.3%). Acute renal failure requiring renal replacement therapy was the third most common complication, occurring in 4.9% of patients.
Rates of major vascular complications may be overestimated owing to rapidly evolving TAVI technology.
The most common adverse effects associated with TAVI are heart block, vascular complications, and renal failure. The type of transcatheter valve and the route of implantation are associated with observed variations in the risks for some adverse effects.
Heart and Stroke Foundation of Canada.
Abstract Patients with isolated medial knee osteoarthritis are often candidates for both unicompartmental knee arthroplasty and total knee arthroplasty and must choose between these 2 options. We ...interviewed 20 such patients to describe their decision support needs and 14 knee arthroplasty surgeons to describe their requirements in supporting patients' decision making. Patients and surgeons both desired active patient participation in the decision. Of 14 surgeons, 13 identified a knowledgeable patient as the most important factor in facilitating decision making, but many worried about confusing patients from information overload. Patients, on the other hand, demonstrated poor knowledge of the advantages and disadvantages of each surgical option, and 17 of 20 desired supplemental educational resources. Thus, most patients choosing between unicompartmental knee arthroplasty and total knee arthroplasty would appreciate and benefit from a decision support intervention.
Abstract Background With the goal of minimizing patient radiation exposure, many centres have adopted prospective ECG-gated computed tomographic coronary angiography. Since image acquisition occurs ...only during ventricular diastasis, the ability to measure left ventricular (LV) ejection fraction (EF) and LV volumes has been lost. Given that LV volumes have prognostic value, the ability to estimate LV end diastolic volume (EDV) may be clinically desirable. Objective We sought to predict LV EDV using CT coronary angiography (CTA) images obtained during ventricular diastasis. Methods Consecutive patients who underwent retrospective ECG-gated CTA were enrolled. Images were reconstructed at the 75% phase and at end-diastole. LV and left atrial (LA) volumes were measured. Results A total of 153 consecutive patients were analyzed (mean age = 56.7 ± 11.2 years; men = 56.2%). The mean LV EDV and EF were 144.4 ± 40.2 mL and 63.4 ± 9.9%, respectively. There appeared to be a very strong linear relationship between the 75% phase LV volume and LV EDV with an R2 of 0.993. Using LV and LA volumes at the 75% phase, a prediction model of LV EDV was developed (LV EDV = (1.021 × 75% phase LV volume) + (0.259 × 75% phase LA volume), adjusted R2 = 0.995). Conclusion LV EDV can be estimated using CTA data obtained during ventricular diastasis. Further studies are needed to demonstrate that such estimates of LV EDV have incremental prognostic value over coronary artery disease severity assessment with prospective ECG-gated CTA.
Symptoms of orthostatic intolerance, e.g., following prolonged bed rest and microgravity exposure, are associated with reductions in cerebral blood flow. We tested the hypothesis that spontaneously ...breathing through an impedance threshold device (ITD) would attenuate the fall in cerebral blood flow velocity (CBFV) during a hypotensive orthostatic challenge and reduce the severity of reported symptoms.
While breathing through either an active ITD (-7 cm H2O inspiratory impedance) or a sham ITD (no impedance), 19 subjects performed a squat stand test (SST). Symptoms upon stand were recorded on a 5-point scale (1 = normal; 5 = faint) of subject-perceived rating (SPR). To address our hypothesis, only data from symptomatic subjects (SPR > 1 during the sham trial) were analyzed (N = 9). Mean arterial blood pressure (MAP) and mean CBFV were measured continuously throughout the SST and analyzed in time and frequency domains.
Breathing with the active ITD during the SST reduced the severity of orthostatic symptoms in eight of the nine symptomatic subjects (sham ITD SPR, 1.9 +/- 0.1; active ITD SPR, 1.1 +/- 0.1), but there was no statistically distinguishable difference in the reduction of mean CBFV between the two trials (sham ITD, -39 +/- 3% vs. active ITD, -44 +/- 3%). High frequency oscillations in mean CBFV, however, were greater during the active ITD trial (7.8 +/- 2.6 cm x s(-2)) compared with the sham ITD trial (2.5 +/- 0.9 cm x s(-2)).
Higher oscillations in CBFV while breathing with the active ITD may account for the reduction in symptom severity during orthostatic hypotension despite the same fall in absolute CBFV.
The preservation of cerebral blood flow with orthostatic hypotension (e.g., following prolonged bed rest or microgravity exposure) is vital for the attenuation of symptoms and the maintenance of ...consciousness. We tested the hypothesis that decreasing mean arterial pressure (MAP) by > 30% is associated with compromised cerebral autoregulation and orthostatic symptoms during a squat-stand test (SST).
There were 19 subjects who performed an SST. MAP and middle cerebral artery blood flow velocity (CBFV) were recorded continuously. Subjects were divided retrospectively into those who reported: (1) at least one orthostatic symptom (Sx; n=9); or (2) no orthostatic symptoms (NSx; n=10). Cerebral autoregulation was assessed via the calculation of time to nadir and time to recovery for MAP and CBFV and linear regression analysis of the dynamic changes in MAP and CBFV (within 10 s of standing).
On standing, MAP decreased by 37 +/- 2% (NSx) and 42 +/- 4% (Sx) (p = 0.100). CBFV fell by 6% more in the Sx group than in the NSx group (NSx, -33 +/- 1% vs. Sx, -39 +/- 3%, p = 0.032). Cerebral autoregulation remained intact in both groups as indicated by: (1) a faster time to nadir for CBFV compared with MAP; (2) a faster time to recovery for CBFV compared with MAP; and 3) a poor correlation between CBFV and MAP responses on standing (NSx R2 = 0.43; Sx R2 = 0.60).
Lower cerebral blood flow during severe hypotension may account for the reporting of orthostatic symptoms, despite the maintenance of cerebral autoregulation.
Abstract Pd/BEA is chosen as a model passive NO x adsorber (PNA) to elucidate the effect of the feed gas composition on the NO x adsorption/desorption behavior. The Brønsted acid and the partially ...hydrolyzed framework Al (P‐HAl(OH)) sites in HBEA adsorb NO and NO 2 under dry conditions. Moreover, the performance of HBEA is not affected by CO, while CO inhibits nitrate formation and promotes NO adsorption via the Pd(NO)(CO) complexes formation over Pd/BEA. H 2 O inhibits NO adsorption over the Brønsted acid and P‐HAl(OH) sites, and ionic Pd is the only active site for NO x adsorption under wet conditions. Furthermore, NO adsorption over hydrated Pd (Pd 2+ (OH)(NO)(H 2 O) 3 ) is weaker than NO adsorption over bare ionic Pd (Z 2 Pd 2+ (NO), ZPd 2+ (OH)(NO)). Dehydration of Pd 2+ (OH)(NO)(H 2 O) 3 forms more stable ZPd 2+ (OH)(NO) during desorption. The NO adsorption capacity of Pd/BEA improves in the presence of CO under both dry and wet conditions by forming a stable carbonyl–nitrosyl complex.
In Canada, graduating medical students consider many factors, including geographic, social, and academic, when ranking residency programs through the Canadian Residency Matching Service (CaRMS). The ...relative significance of these factors is poorly studied in Canada. It is also unknown how students differentiate between their top program choices. This survey study addresses the influence of various factors on applicant decision making.
Graduating medical students from all six Ontario medical schools were invited to participate in an online survey available for three weeks prior to the CaRMS match day in 2010. Max-Diff discrete choice scaling, multiple choice, and drop-list style questions were employed. The Max-Diff data was analyzed using a scaled simple count method. Data for how students distinguish between top programs was analyzed as percentages. Comparisons were made between male and female applicants as well as between family medicine and specialist applicants; statistical significance was determined by the Mann-Whitney test.
In total, 339 of 819 (41.4%) eligible students responded. The variety of clinical experiences and resident morale were weighed heavily in choosing a residency program; whereas financial incentives and parental leave attitudes had low influence. Major reasons that applicants selected their first choice program over their second choice included the distance to relatives and desirability of the city. Both genders had similar priorities when selecting programs. Family medicine applicants rated the variety of clinical experiences more importantly; whereas specialty applicants emphasized academic factors more.
Graduating medical students consider program characteristics such as the variety of clinical experiences and resident morale heavily in terms of overall priority. However, differentiation between their top two choice programs is often dependent on social/geographic factors. The results of this survey will contribute to a better understanding of the CaRMS decision making process for both junior medical students and residency program directors.
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