The evolving costs of intracoronary stents.

BACKGROUND: As stenting practice has evolved to include greater numbers of stents and adjunctive balloon catheters per case, concern has focused on the increasing costs of equipment for the delivery of stents. METHODS AND RESULTS: To evaluate temporal changes in costs of intracoronary stenting, we examined total costs, catheterization laboratory equipment costs, equipment utilization, and nonlaboratory hospital costs for stent cases for two time periods: Period I (n = 46; 3 months in 1995 involving routine warfarin anticoagulation) and Period II (n = 129; 4 months during which warfarin was being abandoned). Overall costs declined from Period I ($11,293+/-$7672) to Period II ($9819+/-$3636) (p = 0.074). Catheterization laboratory equipment expenditures rose (Period I, $3823+/-$1394 vs Period II, $4278+/-$1533), whereas noncatheterization laboratory hospital costs declined significantly (Period I, $7281+/-$7179 vs Period II, $5560+/-$3420). The difference in costs was most notable when taking into account the deletion of warfarin anticoagulation. Costs declined by $2428 for patients in Period II in whom warfarin was not prescribed (p < 0.05 vs patients in Period I). CONCLUSIONS: We conclude that despite the increasing costs for equipment of stent cases, our overall costs of providing stents declined as warfarin anticoagulation was abandoned.

Cost advantages of an ad hoc angioplasty strategy.

OBJECTIVES: We sought to determine the cost advantage of a strategy of same-sitting diagnostic catheterization and percutaneous transluminal coronary angioplasty (PTCA) (ad hoc) in comparison with staged PTCA. BACKGROUND: It is widely assumed that an ad hoc strategy lowers costs by reducing the length of hospital stay (LOS). However, this assumption has not been examined in a contemporary data set. METHODS: We studied 395 patients undergoing PTCA during 6 consecutive months. Cost analysis was performed using standard cost-accounting methods and a mature cost-accounting system. Costs were examined within three clinical strata based on the indication for PTCA (stable angina, unstable angina and after myocardial infarction [MI]). RESULTS: For the entire patient cohort, there was no significant cost advantage of an ad hoc approach within any of the strata, although there was a nonsignificant trend toward an ad hoc approach in patients with stable angina. For patients treated with conventional balloon PTCA alone, the lack of a significant difference between ad hoc and staged strategies persisted. For patients who received stents, there was a significant cost advantage of an ad hoc approach in all three clinical strata. An important cost driver was the occurrence of complications. Differences in the rates of complications did not reach statistical significance between ad hoc and staged strategies, but even a small trend toward greater complications in patients who had the ad hoc strategy negated cost and LOS advantages. Our study had the power to detect significant cost differences of $1,300 for patients with stable angina, $2,100 for patients with unstable angina and $2,500 for post-MI patients. It is possible that we failed to detect smaller cost advantages as significant. CONCLUSIONS: A cost savings with an ad hoc strategy of PTCA could not be consistently demonstrated. The cost advantage of an ad hoc approach may be most readily realized in clinical settings where the intrinsic risks are low (e.g., stable angina) or in which the device used carries a reduced risk of complications (e.g., stenting), because even a small increase in the complication rate will negate any financial advantage of an ad hoc approach.

Economic impact of angioplasty salvage techniques, with an emphasis on coronary stents: a method incorporating costs, revenues, clinical effectiveness and payer mix.

OBJECTIVES: We sought to broaden assessment of the economic impact of percutaneous transluminal coronary angioplasty (PTCA) revascularization salvage strategies by taking into account costs, revenues, the off-setting effects of prevented clinical complications and the effects of payer mix. BACKGROUND: Previous economic analyses of PTCA have focused on the direct costs of treatment but have not accounted either for associated revenues or for the ability of costly salvage techniques such as coronary stenting to reduce even costlier complications. METHODS: Procedural costs, revenues and contribution margins (i.e., "profit") were measured for 765 consecutive PTCA cases to assess the economic impact of salvage techniques (prolonged heparin administration, thrombolysis, intracoronary stenting or use of perfusion balloon catheters) and clinical complications (myocardial infarction, coronary artery bypass graft surgery [CABG] or acute vessel closure with repeat PTCA). To assess the economic impact of various salvage techniques for failed PTCA, we used actual 1995 financial data as well as models of various mixes of fee-for-service, diagnosis-related group (DRG) and capitated payers. RESULTS: Under fee-for-service arrangements, most salvage techniques were profitable for the hospital. Stents were profitable at almost any level of clinical effectiveness. Under DRG-based systems, most salvage techniques such as stenting produced a financial loss to the hospital because one complication (CABG) remained profitable. Under capitated arrangements, stenting and other salvage modalities were profitable only if they were clinically effective in preventing complications in > 50% of cases in which they were used. CONCLUSIONS: The economic impact of PTCA salvage techniques depends on their clinical effectiveness, costs and revenues. In reimbursement systems dominated by DRG payers, salvage techniques are not rewarded, whereas complications are. Under capitated systems, the level of clinical effectiveness needed to achieve cost savings is probably not achievable in current practice. Further studies are needed to define equitable reimbursement schedules that will promote clinically effective practice.

Femoral artery pseudoaneurysm in a monkey.

Pseudoaneurysm formation as a complication of routine blood collection was diagnosed in a monkey. Damage to the femoral artery resulted in hematoma formation with secondary organization, encapsulation, and vascular communication. Progressive lameness and muscular atrophy were the primary clinical signs. Surgical correction of the artery defect helped resolve the monkey's lameness and muscle atrophy.

The value of skull radiography in children with intracranial tumours.

A consecutive series of 106 children with intracranial tumours has been reviewed with special reference to the findings of cranial computed tomography (CT) and plain skull radiography. This review showed that if cranial CT is to be performed, routine plain skull radiographs provide no further information of value in diagnosis. Special projections of the optic canal or internal auditory meatus may be of value in selected patients.

Increase in the phosphotransferase specific activity of purified Rous sarcoma virus pp60v-src protein after incubation with ATP plus Mg2+.

pp60v-src, the product of the Rous sarcoma virus src gene, was partially purified by immunoaffinity chromatography from extracts of Rous sarcoma virus-transformed field vole cells. Incubation of this preparation with ATP plus Mg2+ and subsequent repurification by chromatography on hexylamine-agarose resulted in a net increase in the specific activity of the src protein kinase. This increase in phosphotransferase activity was detected by using a variety of substrates including casein, tubulin, and a 34,000-dalton protein presumed to be an in vivo target substrate of pp60v-src. In all cases, the phosphorylation was at tyrosine residues, and the kinase activity was inhibited by preincubation of the enzyme with immunoglobulin G prepared from tumor-bearing rabbit sera. The implications of these results for the regulation and control of pp60v-src-associated kinase activity are discussed.

Physical modification of purified Rous sarcoma virus pp60v-src protein after incubation with ATP/Mg2+.

Using partially purified enzyme preparations, we show that incubation of the Rous sarcoma virus transforming protein kinase, pp60v-src, with Mg2+ and ATP at concentrations near or above the enzyme's Km for ATP resulted in a physical modification of the pp60v-src polypeptide. Under such conditions, a portion of pp60v-src was converted to a form that migrated more slowly in SDS-polyacrylamide gels than enzyme incubated without ATP or with low concentrations of ATP. Comparative tryptic peptide mapping of pp60v-src incubated with low and high levels of ATP revealed that more extensive tyrosine phosphorylation of the pp60v-src polypeptide occurred at the higher concentrations of ATP. This more extensive phosphorylation was characterized by the appearance of several new phosphorylated tyrosine residues on both the amino-terminal and carboxy-terminal portions of the pp60v-src molecule. The possible consequences of these modifications on the protein kinase activity of pp60v-src, and the functional regulation of retrovirus transforming proteins in general, are discussed.

Specific proteolytic fragmentation of p60v-src in transformed cell lysates.

Work involving the transforming protein, p60v-src, of Rous sarcoma virus has resulted in the extensive characterization of its protein structure and associated phosphotransferase activity. However, in many investigations proteolytic fragments (principally p52v-src) of the src protein are actually studied. Here, we emphasize potential problems in the interpretation of experimental results in which the proteolytic fragmentation of p60v-src may be involved and offer several means for the complete prevention of this p60v-src degradation.