Identification of patients at high risk for adverse coronary events while awaiting routine coronary angioplasty

[Development and validation of a prediction model to identify HIV+ patients with drug-related problems. A prediction study]

OBJECTIVE

To develop and validate a prediction model for the detection of drug-related problems (DRP) in patients on antiretroviral treatment during their regular monitoring in Pharmaceutical Care Clinics before dispensing drugs. MEHOD: Open multicentre prospective study. HIV patients with and without DRP were included. Demographic, clinical and pharmacotherapy variables (related and unrelated to antiretroviral treatment) were included in the model design. To find prognostic factors for DRP, a binary logistic regression model was created after performing a univariate analysis that identified independent variables related to DRP these variables were introduced in the multivariate model for the final selection. Model validity was determined by the shrinkage method and the discriminatory power by Harrell's C-index.

RESULTS

733 patients were included. The variables "adherence", "prescription of drugs needing dosage adjustment", and "total number of drugs prescribed (apart from the antiretroviral treatment)" were independently related to the appearance of DRP. Probabilities predicted by the model, customising the coefficients using the uniform shrinkage method, showed a R(2)=0.962 for the construction sample and a R(2)=0.872 for the validation sample. The discriminatory capacity of the model was 0.816 for the construction sample and 0.779 for the validation sample.

CONCLUSIONS

The developed and validated model enables detection of patients on antiretroviral treatment who are at a higher risk for experiencing a DRP. The prediction variables employed are commonly used in patient's pharmacotherapy record, allowing the model to be used in routine clinical practice.

The association of hypertriglyceridemia with cardiovascular events and pancreatitis: a systematic review and meta-analysis

BACKGROUND

Hypertriglyceridemia may be associated with important complications. The aim of this study is to estimate the magnitude of association and quality of supporting evidence linking hypertriglyceridemia to cardiovascular events and pancreatitis.

METHODS

We conducted a systematic review of multiple electronic bibliographic databases and subsequent meta-analysis using a random effects model. Studies eligible for this review followed patients longitudinally and evaluated quantitatively the association of fasting hypertriglyceridemia with the outcomes of interest. Reviewers working independently and in duplicate reviewed studies and extracted data.

RESULTS

35 studies provided data sufficient for meta-analysis. The quality of these observational studies was moderate to low with fair level of multivariable adjustments and adequate exposure and outcome ascertainment. Fasting hypertriglyceridemia was significantly associated with cardiovascular death (odds ratios (OR) 1.80; 95% confidence interval (CI) 1.31-2.49), cardiovascular events (OR, 1.37; 95% CI, 1.23-1.53), myocardial infarction (OR, 1.31; 95% CI, 1.15-1.49), and pancreatitis (OR, 3.96; 95% CI, 1.27-12.34, in one study only). The association with all-cause mortality was not statistically significant.

CONCLUSIONS

The current evidence suggests that fasting hypertriglyceridemia is associated with increased risk of cardiovascular death, MI, cardiovascular events, and possibly acute pancreatitis.Précis: hypertriglyceridemia is associated with increased risk of cardiovascular death, MI, cardiovascular events, and possibly acute pancreatitis.

Treating the right patient at the right time: Access to cardiac catheterization, percutaneous coronary intervention and cardiac surgery

The Canadian Cardiovascular Society Access to Care Working Group was formed with a mandate to use the best science and information available to establish reasonable triage categories and safe wait times for common cardiovascular services and procedures through a series of commentaries. The present commentary discusses the rationale for access benchmarks for cardiac catheterization and revascularization procedures for patients with stable angina, and access benchmarks for cardiac catheterization and surgery for patients with valvular heart disease. Literature on standards of care, wait times and wait list management was reviewed. A survey of cardiac centres in Canada was performed to develop an inventory of current practices in identifying and triaging patients. The Working Group recommends the following medically acceptable wait times for access to cardiac catheterization: 14 days for symptomatic aortic stenosis and six weeks for patients with stable angina and other valvular disease. For percutaneous coronary intervention in stable patients with high-risk anatomy, immediate revascularization or a wait time of 14 days is recommended; six weeks is recommended for all other patients. The target for bypass surgery in those with high-risk anatomy or valve surgery in patients with symptomatic aortic stenosis is 14 days; for all others, the target is six weeks. All stakeholders must affirm the appropriateness of these standards and work continuously to achieve them. There is an ongoing need to continually reassess current risk stratification methods to limit adverse events in patients on waiting lists and assist clinicians in triaging patients for invasive therapies.

Disease progression and adverse events in patients listed for elective percutaneous coronary intervention

OBJECTIVE

To record disease progression and the timing of adverse events in patients on a waiting list for elective percutaneous coronary intervention (PCI).

DESIGN

Observational prospective study.

SETTINGS

A UK tertiary cardiothoracic centre, at a time when waiting lists for PCI were up to 18 months.

PATIENTS

145 patients (116 men, median age 59.5 years) placed on an elective waiting list for PCI between October 1998 and September 1999.

MAIN OUTCOME MEASURES

Adverse events recorded were death, myocardial infarction, need for urgent hospital admission because of unstable angina, and need for emergency revascularisation while waiting for PCI.

RESULTS

During a median follow up of 10 months (range 1-18 months), nine (6.2%) patients experienced an adverse event. Eight (5.52%) patients were admitted with unstable angina as emergencies. One was admitted with a myocardial infarction. Twenty nine (20.0%) patients had significant disease progression at the time of the repeat angiogram before PCI. In 10 (7%), disease had progressed so that PCI was no longer feasible and patients were referred for coronary artery bypass graft. Sixteen (11%) were removed from the PCI waiting list because of almost complete resolution of their anginal symptoms.

CONCLUSION

Adverse coronary events and clinically significant disease progression occur commonly in patients waiting for PCI. Despite the presence of severe coronary lesions, myocardial infarction was rare and no patients died while on the waiting list. Resolution of anginal symptoms was also comparatively common. The pathophysiology of disease progression frequently necessitates a change in the treatment of patients waiting for PCI.

Waiting times, revascularization modality, and outcomes after acute myocardial infarction at hospitals with and without on-site revascularization facilities in Canada

OBJECTIVES

This study was designed to determine whether admission to a Canadian hospital with on-site revascularization (invasive hospital) affected revascularization choice, timing, and outcome compared with community (non-invasive) hospitals.

BACKGROUND

Health care systems in Canada are characterized by relative restraint in diffusion of tertiary cardiovascular services, with capacity for revascularization procedures concentrated in large regional referral centers.

METHODS

We used linked administrative data and a clinical registry to follow-up 15,166 Ontario patients who underwent revascularization within the year after their index acute myocardial infarction (MI). Outcomes included recurrent urgent cardiac hospitalization, hospital bed-days, and death within the same year after the index admission. We adjusted for age, gender, socioeconomic status, illness severity, attending physician specialty, and academic hospital affiliation.

RESULTS

After adjusting for baseline factors, patients admitted to invasive hospitals were more likely to receive angioplasty than bypass surgery (adjusted odd ratio: 1.85; 95% confidence interval: 1.68 to 2.04, p < 0.001). The converse pattern was seen for patients admitted to community hospitals. Median revascularization waiting times were significantly shorter at invasive hospitals (12 vs. 48 days, p < 0.001). Patients admitted to invasive hospitals had fewer cardiac re-admissions (41.5 vs. 68.9 events per 100 patients, p < 0.001) before their first revascularization and consumed fewer hospital bed-days (379 vs. 517 per 100 patients, p < 0.001). There were no differences in outcomes beyond revascularization.

CONCLUSIONS

Outcome advantages associated with timely post-MI revascularization highlight the importance of organizing revascularization referral networks and facilitating access to revascularization for patients with acute coronary syndromes admitted to community hospitals in Canada.

Role of prolonged intravenous heparin in unstable angina patients prior to coronary angioplasty

BACKGROUND

The optimal timing of coronary angioplasty in unstable angina patients is controversial. Early reports suggested using 3-5 days of intravenous heparin and aspirin for plaque stabilization before angioplasty. There is no clearcut data in this regard from the published literature. The purpose of this study was to evaluate whether delaying the angioplasty in order to stabilize the plaque affected the outcome.

METHODS

We reviewed the hospital course of patients who were admitted with unstable angina through the emergency room and ruled out for myocardial infarction, and who required angioplasty during the index hospitalization. To diminish the influence of coronary stenting and glycoprotein IIb/IIIa receptor blockade, we reviewed all patients admitted during 1994.

RESULTS

Of the 305 patients, 166 patients received < or = 48 hours and 139 patients received > 48 hours of intravenous heparin infusion before angioplasty. Both groups were well-matched. The procedural success was similar in both the groups (98% vs 97%, P = 0.72). The complication rate was similar in both groups, including abrupt closure, emergency bypass surgery, myocardial infarction and death. Length of hospital stay was significantly prolonged in the group with > 48 hours of heparin infusion (4.4 +/- 3.0 vs 7.4 +/- 3.6 days; P < 0.001).

CONCLUSION

In patients with unstable angina undergoing angioplasty, prolonged duration of heparin infusion influenced the procedural outcome or postprocedural complications, but prolonged the hospital stay. These data suggest that early angioplasty of unstable angina patients is safe and may be cost-effective, even in the absence of stenting and potent antiplatelet agents. However, prospective, randomized trials are needed to clarify the need for and duration of heparin infusion prior to angioplasty in unstable angina patients.

Revascularization of patients with unstable coronary artery disease: the case for early intervention

In unstable angina, there are data to suggest a substantial risk of recurrent ischemia, infarction, and death when early angiography and/or revascularization have been deferred. Conversely, it has been suggested that early angiography and revascularization are more dangerous than deferred procedures. Critical review of the literature, however, suggests that there is no specific risk inherent in early intervention, but rather that patients who cannot wait are at higher risk anyway. The most valuable data on the comparison of an "early invasive" and a "conservative" strategy in unstable angina come from the Thrombolysis in Myocardial Ischemia (TIMI) IIIB study. The results show no major difference in outcome between groups (despite a high intervention rate in the conservative group), but a shorter hospital stay, lower drug use, and fewer rehospitalizations in the group treated according to the early invasive strategy. These results have been interpreted as favoring early intervention, due to the potential for a shorter hospital stay (a major determinant of cost in many countries) because of the possibility of achieving complete diagnosis and treatment within several days of admission, with good results. In addition, since the inception of the TIMI IIIB study, there have been major improvements in the field of angioplasty, such as the increased use of stents and the availability of safe and effective glycoprotein (GP) IIb-IIIa inhibitors. Thus, the pathophysiology, the excellent results of early intervention, and the recent improvements in angioplasty and its medical and pharmacologic environment, provide a strong rationale for early intervention.

Does a waiting time for elective coronary angioplasty affect the primary success rate?

OBJECTIVE

To evaluate the effect of the waiting time for elective percutaneous transluminal coronary angioplasty (PTCA) on the primary success rate.

SETTING

University hospital in The Netherlands.

PATIENTS

A cohort of 817 consecutive patients awaiting elective PTCA. Scheduled PTCA was performed in all 817 patients, involving 1237 coronary lesions.

MAIN OUTCOME MEASURES

The relation between procedural success and the duration of the waiting time was evaluated. Major cardiac events, that is, death and myocardial infarction while awaiting PTCA, were documented. Alterations in lesion characteristics during the waiting time were assessed in unsuccessful procedures.

RESULTS

Elective PTCA was performed within one to six weeks after acceptance in 388 patients (587 lesions; 47.5%), between six and 12 weeks in 203 patients (308 lesions; 25%), and after more than 12 weeks in 226 patients (342 lesions; 27.5%). The procedural success rates in the defined time intervals were 97%, 99%, and 97% in ACC/AHA type A lesions, 93%, 87% and 90% in type B lesions, and 63%, 55% and 38% in type C lesions respectively; 96% of type C lesions were total coronary occlusions. There was a significant decrease in primary success rate in type C lesions after a waiting time beyond 12 weeks. A reasonable explanation for an unsuccessful angioplasty related to alterations in lesion characteristics during the waiting time was documented in only four of 115 procedures.

CONCLUSIONS

The primary success in type A and B lesions is unaffected by the duration of a waiting period for elective PTCA. A waiting time of more than 12 weeks is associated with a lower success rate in patients with total coronary occlusions.

The natural history of unheralded complex coronary plaques

OBJECTIVES

This study sought to assess the behavior of unheralded complex lesions in patients with no previous history of acute coronary ischemia.

BACKGROUND

Angiographically complex coronary stenoses appear to originate from plaque disruption and are associated with rapid progression early and late after acute coronary events. Complex lesions may occur without symptoms, but neither the incidence nor the behavior of these unheralded complex lesions is known.

METHODS

We studied 222 patients with chronic stable angina who were on a waiting list for single-vessel percutaneous transluminal coronary angioplasty of an unoccluded lesion and underwent repeat angiography immediately before the procedure as part of routine practice or shortly after a coronary event. Patients with a previous episode of myocardial infarction or unstable angina were not included. Angiograms were analyzed quantitatively and qualitatively using established methods. A change of +/- 15% stenosis severity or total coronary occlusion defined categoric change.

RESULTS

At first angiography, there were 52 unheralded complex target lesions (23%) and 170 smooth target stenoses (77%). Stenosis severity did not differ between complex and smooth target lesions at first and second angiography at a mean (+/- SD) interval of 7 +/- 4 months. At follow-up, seven complex lesions had progressed (14%) compared with six smooth lesions (4%, p < 0.02). Total occlusion developed in four complex lesions and one smooth lesion. Overall, complex stenoses progressed by 3 +/- 13% compared with 0.5 +/- 7% in the smooth stenoses (p = 0.15). Complex stenoses were 4.2 times more likely to progress than smooth stenoses (95% confidence interval 1.2 to 15.2 [Cornfields method]). Clinical events developed in seven patients. One complex lesion regressed and became smooth, and three smooth stenoses became complex at follow-up.

CONCLUSIONS

Morphologically complex stenosis can develop without an episode of acute coronary ischemia and are relatively common in patients awaiting single-vessel angioplasty. Our study demonstrates that like their clinically heralded counterparts, these unheralded complex stenoses are at higher risk of progression than smooth stenoses.