The role of the sizing balloon in selection of the patent foramen ovale closure device size.

OBJECTIVES: To find a correlation between the patent foramen ovale (PFO) size measured by the sizing balloon and the appropriate closure device size. METHODS: The PFO of 57 patients was closed using a sizing balloon. A mathematical model was introduced to relate the PFO balloon waist diameter to the closure device size based on the PFO transformation from a slit-like to a circular form during balloon inflation. According to this model, PFOs smaller than 8 mm should be closed with a 25 mm device, PFOs 8 mm to 11 mm with a 35 mm device, and PFOs larger than 11 mm with an Amplatzer septal occluder. In the first group, 36 patients (63.2%) received an appropriately sized device and six patients (10.5%) received an oversized device. In the second group, 15 patients (26.3%) received an undersized device. RESULTS: A comparison of the PFO dimensions in two views showed that the PFO slit was circular when the balloon was inflated. A six-month echocardiography follow-up was obtained in 46 patients (80.7%). Five patients (13.9%) in the group with an appropriately sized device had a discrete residual shunt during Valsalva. In the second group, five patients (33.3%) had a residual shunt (P = 0.06), of which one was considered large. CONCLUSION: The sizing balloon is helpful in selecting the PFO closure device size. Consequently, the incidence of residual shunt and recurrent events may be reduced.

Mechanisms of neointima formation and remodeling in the porcine coronary artery.

BACKGROUND: To characterize the cells responsible for neointima formation after porcine coronary artery wall injury, we studied the expression of smooth muscle cell (SMC) differentiation markers in 2 models: (1) self-expanding stent implantation resulting in no or little interruption of internal elastic lamina and (2) percutaneous transluminal coronary angioplasty (PTCA) resulting in complete medial rupture and exposure of adventitia to blood components. METHODS AND RESULTS: The expression of alpha-smooth muscle (SM) actin, SM myosin heavy chain isoforms 1 and 2, desmin, and smoothelin was investigated by means of immunohistochemistry and Western blots in tissues of the arterial wall collected at different time points and in cell populations cultured from these tissues. The expression of smoothelin, a marker of late SMC differentiation, was used to discriminate between SMCs and myofibroblasts. Both stent- and PTCA-induced neointimal tissues and their cultured cell populations expressed all 4 markers. The adventitial tissue underlying PTCA-induced lesions temporarily expressed alpha-SM actin, desmin, and SM myosin heavy chain isoforms, but not smoothelin. When placed in culture, adventitial cells expressed only alpha-SM actin. CONCLUSIONS: Our results suggest that SMCs are the main components of coronary artery neointima after both self-expanding stent implantation and PTCA. The adventitial reaction observed after PTCA evolves with a chronology independent of that of neointima formation and probably corresponds to a myofibroblastic reaction.

Collagen application versus manual compression: a prospective randomized trial for arterial puncture site closure after coronary angioplasty.

OBJECTIVES: This study evaluated the safety and efficacy of a newly developed puncture-sealing device consisting of subcutaneous bovine collagen application designed to facilitate local hemostasis after coronary angioplasty. BACKGROUND: The most common local hemostatic procedure after coronary angioplasty consists of heparin discontinuation and delayed sheath removal followed by mechanical compression at the puncture site. METHODS: Between December 1991 and February 1993, 124 patients undergoing coronary angioplasty with either a 6F guiding catheter followed by a heparin infusion for > 12 h or a 7F or 8F guiding catheter with optional heparin infusion were prospectively randomized to either delayed sheath removal followed by manual compression (n = 62) or sheath removal immediately after angioplasty combined with bovine collagen application for puncture site closure (n = 62). Half of the collagen plugs were delivered using measured and half using estimated skin-artery distance. Clinical and duplex sonographic evaluations of the puncture site were performed 24 h later. RESULTS: No significant difference in the incidence of local hematomas was observed. Major complications were false aneurysm, venous thrombosis and arterial occlusion. The incidence of false aneurysm was the same in both groups (4 [7%] of 62). Venous thrombosis (2%) and arterial occlusion (2%) were each recorded in one patient, both in the collagen application group. CONCLUSIONS: Sheath removal and collagen application with this new vascular hemostasis device used directly after coronary angioplasty are not superior to delayed sheath removal after heparin discontinuation followed by mechanical compression. Arterial collagen sealing with this device in its current form is associated with a small but worrisome risk of arterial occlusion.

[Acute myocardial infarction due to spontaneous coronary artery dissection]. / Infarctus aigu du myocarde secondaire a une dissection coronaire spontanée. A propos de 6 cas.

BACKGROUND: Spontaneous coronary dissection is a rare cause of acute myocardial infarction (AMI). Its aetiology and treatment have not yet been well defined. In this report, we review the clinical presentation, the aetiology, the risk factors and the treatment of 6 cases of AMI due to spontaneous coronary dissection. METHODOLOGY AND RESULTS: We have reviewed 1100 cases of AMI having undergone coronary angiography in our institution during the period December 1999 to January 2004. Six cases (0.5%; 5 men, mean age: 38 years) in which spontaneous coronary dissection had been retained as final aetiology were further analyzed. Four patients had no cardiovascular risk factors but, interestingly, in all 6 patients we found a clear triggering factor of the acute event: extreme physical stress (5), or psychological stress (1). Thrombolysis had been performed in 5 patients, and the coronary angiography carried out thereafter showed a dissection of the left anterior descending coronary (2 cases), of the right coronary artery (3 cases) or of the left circumflex artery (1 case). All patients had a preserved coronary flow (TIMI 3). On the basis of the angiographical findings, medical treatment (4 patients), coronary artery by-pass grafting (1 patient), or percutaneous angioplasty with stenting (1 patient) were performed. The only major cardiac adverse event observed in the early follow up was a sudden acute thrombosis of the coronary stent. CONCLUSION: In young patients without cardiovascular risk factors and presenting with AMI subsequent to a physical or emotional stress, spontaneous coronary artery dissection should imperatively be taken into consideration as a possible diagnosis. Since intravenous thrombolysis may worsen the dissection, we recommend primary emergency coronarography as a diagnostic and (sometimes) therapeutic treatment option.

Quantitative assessment with intracoronary ultrasound of the mechanisms of restenosis after percutaneous transluminal coronary angioplasty and directional coronary atherectomy.

The mechanisms of immediate and late changes after percutaneous transluminal coronary angioplasty (PTCA) and directional coronary atherectomy (DCA) were assessed by serial ultrasound imaging in 18 patients treated with PTCA and 16 treated with DCA before, immediately after, and 6 months after coronary interventions. A reduction in plaque area was the main operative mechanism of DCA, explaining 66% of lumen enlargement. In the PTCA group, the increase in lumen area was the result of a more balanced combination of plaque reduction (52% of lumen increase) and increase in total lumen area (48%); p < 0.05 versus DCA. In the PTCA group, this last mechanism was prevalent (p < 0.05) in the lesions showing wall fracture or dissection after treatment and in the lesions with a mixed or calcific composition. In the PTCA group, concentric lesions showed a greater plaque compression than eccentric lesions (p < 0.02). Plaque increase was responsible for 92% and 32% of the late lumen loss after DCA and after PTCA, respectively (p < 0.05). In PTCA patients, a chronic reduction in total vessel area was the main operative mechanism of lumen reduction (67%) and was prevalent in lesions with a mixed or calcific composition. (p < 0.05).

Usefulness of on-line three-dimensional reconstruction of intracoronary ultrasound for guidance of stent deployment.

The additional information provided by automated on-line 3-dimensional (3-D) reconstruction of intracoronary ultrasound (ICUS) was assessed in 42 patients (62 stents) who underwent stent deployment after achieving an optimal quantitative angiographic result. In 10 of 42 patients, 3-D ICUS was also performed before stenting. ICUS images of stents and adjacent reference segments were acquired by using a motorized pullback at a constant speed (1 mm/s) and immediately processed in the catheterization laboratory. Optimal stent expansion was detected by 3-D ICUS in case of complete apposition of stent struts to the vessel wall. Furthermore, an attempt was made to maximize the intrastent lumen area to match lumen area of the reference segment and to cover with stents all the segments with residual significant lesions (plaque burden >50%). Three-dimensional automated reconstruction of ICUS was successful in 8 of 10 patients (80%) before, and in 36 of 42 patients (86%) after stent deployment. In all 8 patients who underwent successful 3-D ICUS assessment before stent implantation, the selection of stent length was facilitated by accurately measuring the lesion length. After stenting, 3-D ICUS modified the management strategy in 21 of 36 patients (58%), triggering additional high-pressure dilatations in 13 patients (36%) and additional stent deployment in 8 (22%). In conclusion, on-line 3-D ICUS facilitates stent selection and strongly modifies the revascularization strategy by accurately detecting stent underexpansion and presence of uncovered lesions.

Coronary angioplasty for isolated non-dominant left circumflex coronary artery disease.

The study describes the clinical findings and results of coronary balloon angioplasty in 134 patients with non-dominant left circumflex coronary artery disease. The immediate angiographic success rate was 97% versus 95% for left anterior descending (P = NS), and 90% for right coronary lesions (P < 0.002). There was no hospital mortality in the circumflex group versus 1.2% in the left anterior descending (P < 0.01), and 0.4% in the right coronary artery group (P = NS). Major non-fatal cardiac complications were significantly lower in the non-dominant left circumflex coronary artery patients (no new Q-wave versus 3% in the left anterior descending, P < 0.0002, and 3% in the right coronary artery group, P < 0.01; no urgent coronary artery bypass grafting versus 2% in the left anterior descending, P < 0.001, and 1% in the right coronary artery group, P = NS). The freedom from chest pain was 63% in 112 patients (84%) with follow-up data available at 24 +/- 18 months, and mean angina class diminished to 0.7 +/- 1.3 (P < 0.001). Consumption of antianginal and other cardiac drugs was diminished during follow-up, and the number of patients on no such drugs increased from 5 to 32% (P < 0.001). Restenosis was found in 19 of 32 patients with repeat coronary angiography (59%). Repeat angioplasty was required in 22 patients during follow-up and in 4 of them (18%) it was done for new lesions. Angioplasty for isolated non-dominant left circumflex coronary artery disease yields excellent immediate and long-term results.

[Study of left ventricular function at rest and post-exercise with thallium-201 myocardial scintigraphy synchronized with ECG]. / Etude de la fonction ventriculaire gauche au repos et dans le post-effort par la tomoscintigraphie myocardique au thallium-201 synchronisée à l'ECG.

ECG-gated Thallium 201 myocardial scintigraphy provides a simultaneous evaluation of left ventricular perfusion and function. The aims of this study were to determine the changes in left ventricular ejection fraction (LVEF) after exercise and at rest 4 hours after exercise and to compare the results with changes in myocardial perfusion and the severity of the coronary artery disease. Sixty-four men with myocardial ischaemia on scintigraphy who had undergone coronary angiography showing significant lesions within 3 months, were compared with 38 normal men. The ejection fraction was calculated with a validated programme (QGS). The change in LVEF between the post-exercise and resting measurement 4 hours after exercise (delta LVEF) was compared in the normal and ischaemic groups (+7 +/- 6.8% vs -5.6 +/- 5%, p < 0.001). The extent of the ischaemia (percentage myocardium unperfused) was significantly greater in the 34 patients who had an over 5% reduction in LVEF on exercise compared with the 30 others who has a less than 5% reductionin LVEF (11.8 vs 6.3%, p < 0.001). There was a linear correlation between the degree of ischaemia and delta LVEF in the 30 patients without a history of infarction (r = -0.76, p < 0.01). The delta LVEF also correlated with the number and site of the coronary lesions. The authors conclude that in this male population, ECG-gated Thallium 201 myocardial scintigraphy can demonstrate a decrease in LVEF after exercise in ischaemic coronary patients whereas it increases in normal subjects. This decrease in LVEF on exercise is correlated with the extent of ischaemia and the severity of the coronary disease and should therefore be taken into account in patient management.

[Comparative study of left ventricular ejection fraction and volume by 2 isotopic methods and contrast angiography]. / Etude comparative des fractions d'éjection et volumes ventriculaires gauches obtenus par deux méthodes isotopiques et par l'angiographie de contraste.

The tomographic mode has replaced the planar mode for radióisotopic studies of myocardial perfusion but not for the study of systolic ventricular function. The aim of this study was to compare monophotonic emission tomography (MPET), the planar mode (PM) and contrast angiography (Angio). The left ventricular volumes and ejection fractions were measured in 111 patients by the tomographic and planar modes and by biplane angiography in 70 of them. The MPET algorithm (QBS software) identified the ventricular endocardium in 96 of the 111 procedures (86%). The mean left ventricular ejection fractions (LVEF) were 57 +/- 17% (MPET, N = 96), 55 +/- 15% (PL, N = 96) and 57 +/- 15% (Angio, N = 70). There was a good correlation of LVEF between MPET and PL and MPET and Angio with negligible bias of 3 +/- 6% and 2 +/- 4% respectively and high correlation coefficients, r = 0.94 (MPET = 1.05*PL-0.2) and r = 0.93 (MPET = 1.1 x Angio-3). The differences between the 95% confidence intervals between MPET and PL and MPET and Angio may be explained by an overestimation of normal LVEF by MPET, especially in patients with low end systolic volumes. In these cases, the difference in LVEF by MEPT and the average LVEF from the 3 techniques was greater: 6 +/- 4% (< or = 20 ml) vs 0 +/- 3% (> 20 ml) (p < 0.0001). The authors conclude that, with the reserve that a high percentage of investigations could not be analysable. MPET seems to be a method of choice for assessing left ventricular systolic function.

[Immediate results of coronary endoprosthesis in threatening or occlusive dissections complicating angioplasty; the Geneva experience]. / Résultats immédiats des endoprothèses coronaires pour dissections menaçantes ou occlusives compliquant une angioplastie; l'expérience genevoise.

Between April 1988 and September 1993, 123 patients (average age 60.4 +/- 8.9 years) underwent coronary stenting for threatening or occlusive dissection complicating angioplasty. The anterograde coronary flow was disturbed in 51% of cases (TIMI-0-2). The artery concerned was the left anterior descending in 59% of cases, the right coronary in 28% of cases, the circumflex in 12% and a coronary bypass graft in 1% of cases. Technically, the stenting was successful in 118 cases (98%) and, in 21 cases, complete stenting of the dissection required the insertion of several stents. The minimal coronary diameter after expansion of the stent was 3.1 +/- 0.6 mm. During hospital follow-up, 3 deaths (3%) and 7 Q-wave infarcts were observed. Twenty-eight patients (23%) developed a haemorrhagic complication, including 2 retroperitoneal and 2 intracerebral bleeds. Eight patients (6%) underwent coronary bypass grafting, as an emergency in 4 cases and semi-electively in another 4 cases. One hundred and five patients (89%) survived the intra-hospital period without major complications (death, Q-wave infarction, emergency coronary bypass surgery or severe haemorrhage). Coronary stenting for threatening or occlusive dissection complicating angioplasty seems to be a reasonable solution and a usually definitive one. The frequency of haemorrhagic complications underlines the need for strict clinical and biological surveillance.

[Treatment of post-coronarography femoral false aneurysm by compression, guided by Doppler echography]. / Traitement des faux-anévrismes fémoraux post-coronarographie par compression guidée par échographie-doppler.

MATERIAL AND METHODS: We evaluated the role of color Doppler US-guided compression in the non-invasive treatment of femoral artery pseudoaneurysms after cardiac catheterization, including 22 PTCA procedures. The diagnosis of 32 pseudoaneurysms in 32 patients was accomplished by detection of the typical US-Doppler pattern consisting of the swirling color Doppler flow and the "to and fro" pulsed Doppler waveform at a mean 3.6 days (1 to 14) after the cardiac catheterization. Thirteen patients had multiple cavity pseudoaneurysms (2 to 4). All the patients immediately underwent compression therapy. RESULTS: Treatment was successful in 42/49 cavities (86%) and 25/32 patients (78%), usually after 1 to 3 compression cycles of 6 to 8 minutes duration. Only one recurrence was noted at the 24 hour US-Doppler follow-up. In all cases, pain relief during compression was an excellent clinical sign of hemostatic plug formation and conversion from pseudoaneurysm to simple hematoma. Failures occurred among patients under high dose anticoagulants in spite of 4 to 10 compression cycles. COMMENTARY: In conclusion, color Doppler US-guided compression of post-cardiac catheterization pseudoaneurysms should be the first line therapeutic modality, even in cases of multiple cavities and among patients under effective anticoagulation therapy.

Ischemic stroke as the presenting manifestation of localized systemic cancer.

A cerebral infarct due to a thrombosis of the left pericallosal artery was the first manifestation of an ovarian adenocarcinoma in a 42-year-old woman. A paraneoplastic origin was suggested by the observation that this patient had chronic intravenous coagulation and subsequently developed migratory thrombophlebitis (Trousseau's syndrome) despite high dose vitamin K antagonists therapy. This was supported by the fact that all manifestations of the hypercoagulable state disappeared following surgical cure of the cancer. Because cerebral infarction can be the first manifestation of a potentially curable cancer, patients with a cerebral infarct of an unknown etiology should be investigated for a malignant process, if there is laboratory or clinical evidence od disseminated intravascular coagulation.

Incidence of atrial fibrillation after percutaneous closure of patent foramen ovale and small atrial septal defects in patients presenting with cryptogenic stroke.

OBJECTIVE: The occurrence of atrial fibrillation after percutaneous closure of a patent foramen ovale for cryptogenic stroke has been reported in a variable percentage of patients. However, its precise incidence and mechanism are presently unclear and remain to be elucidated. DESIGN: Prospective follow-up study. PATIENTS: Ninety-two patients undergoing a percutaneous patent foramen ovale closure procedure (closure group) for cryptogenic stroke were compared with a similar group of 51 patients, who were medically treated. METHODS: A systematic arrhythmia follow-up protocol to assess the incidence of AF was performed including a 7-day event-loop recording at day 1, after 6 and 12 months in patients of the closure group and compared with those of the medically treated group. RESULTS: The incidence of AF was similar in both study groups during a follow-up of 12 months, including 7.6% (95% CI: 3.1-15.0%) in the closure and 7.8% (95% CI: 2.18-18.9%) in the medically treated group (P=1.0). The presence of a large patent foramen ovale was the only significant risk factor for the occurrence of AF as demonstrated by a multivariate Cox regression analysis (95% CI, 1.275-20.018; P=0.021). CONCLUSIONS: Our findings indicate that patients with cryptogenic stroke and patent foramen ovale have a rather high incidence of AF during a follow-up of 12 months. Atrial fibrillation occurred with a similar frequency whether the patent foramen ovale/atrial septal defect was successfully percutaneously closed or was medically managed. The presence of a large patent foramen ovale was the only significant predictor of AF occurrence during follow-up.

[Overweight, obesity and underweigh in Switzerland: results of the 2000 Nutri-Trend Study]. / Ubergewicht, Adipositas und Untergewicht in der Schweiz: Resultate der Nutri-Trend-Studie 2000.

The Nutri-Trend-Study 2000 conducted by Nestlé Suisse SA and supported by the Swiss Federal Office of Public Health collected data on body weight and height of a random sample (n = 1004) of persons aged 18-54 years living in Switzerland. 3% of participants are underweight (BMI < 18.5 kg/m2), 26% overweight (BMI 25-29.9 kg/m2), 5% obese (BMI > or = 30 kg/m2) and 66% are of normal weight (BMI 18.5-24.9 kg/m2). Nutritional knowledge and attitudes of the BMI-groups do not differ substantially. All groups but especially participants with a BMI of 25+ should be better informed about the health consequences of an unbalanced diet. Furthermore they should be encouraged to adopt a physically active lifestyle and a healthy diet to remain within the BMI-range of normal weight or to reduce overweight.

Use of locally delivered conventional drug therapies.

Coronary artery restenosis remains the major limitation of balloon angioplasty and occurs in 30-50% of initially successful procedures. Our current understanding of pathophysiology of restenosis suggests that it involves three inter-related phases; (1) acute effects of thrombosis, (2) neointimal proliferation, and (3) acute recoil and chronic remodelling. In an attempt to prevent vessel restenosis both systemic and site-specific pharmacotherapy have been investigated. Although successful in animal models, systemically administered pharmacological agents for the prevention of restenosis in humans have not been effective. The local administration of compounds such as heparin, anti-thrombin agents, colchicine, angiopeptin, antineoplastic agents, calcium antagonists, nitrates, forskolin, cytochalasin B, protein kinase inhibitors and dexamethasone have been shown to reduce neointimal formation in animal models of restenosis. Clinical trials have demonstrated the feasibility of the local administration of heparin using both InfusaSleeve and Dispatch drug delivery catheters. Preliminary results on long-term prevention of restenosis by heparin appear promising using the Dispatch delivery device. In addition, a multicentre trial investigating the effectiveness of cytochalasin B delivered using the Microporous Infusion Catheter for the prevention of restenosis is currently underway. Rapid progress in our understanding of the complex pathophysiology of restenosis and the development of more effective pharmacological agents and atraumatic site specific delivery modalities ensure a promising future for local delivery strategies.

Limits of thallium-201 exercise scintigraphy to detect coronary disease in patients with complete and permanent bundle branch block: a review of 134 cases.

We reviewed the records of 68 patients with right bundle branch block (RBBB) and 66 patients with left bundle branch block (LBBB), who had undergone thallium-201 exercise scintigraphy and coronary arteriography, to determine the sensitivity, specificity, and positive and negative predictive values of thallium-201 imaging for the detection of coronary artery disease in the presence of intraventricular conduction abnormalities. In patients with RBBB the sensitivity, specificity, and positive and negative predictive values were, respectively, 83%, 89%, 79%, and 92% for the anteroseptal region and 83%, 84%, 83%, and 84% for the inferoposterior region. In patients with LBBB these values were, respectively, 94%, 33%, 36%, and 93% for the anteroseptal region and 77%, 90%, 81%, and 88% for the inferoposterior region. In this second group defects limited to the septal region were a good predictor of false positive scintigrams (9/10 cases), but if apical defects used as the sole criterion for detecting lesions in the left anterior descending artery improved the specificity to 85%, the sensitivity was greatly reduced (35%). We conclude that exercise scintigraphy is a reliable method for detection of coronary lesions in patients with RBBB and in patients with LBBB and inferoposterior perfusion defects, but it is unable to discriminate between normal subjects and patients with coronary disease in the presence of LBBB and anteroseptal perfusion defects. In addition, limited septal defects are highly suggestive of false positive scintigrams in this latter group of patients.

Improving results of bailout coronary stenting after failed balloon angioplasty.

Stent implantation can be a valuable alternative to emergent bypass surgery to treat established or threatening abrupt closure following coronary balloon angioplasty. To evaluate several sequentially introduced changes in our practice of bail-out stenting, we compared the first (group I) and second half (group II) of our single center experience (n = 88). Use of bailout stenting increased over time (2% of all angioplasty procedures in group I vs. 6% in group II, P < 0.001), more often to prevent rather than to reverse abrupt closure. Technical success of stent implantation was unchanged (95% vs. 93%), and there was a decreasing trend for stent thrombosis (14% vs. 5%), in-hospital death (5% vs. 2%), Q-wave myocardial infarction (9% vs. 7%), and requirement for surgery (9% vs. 7%). The incidence of non-Q-wave myocardial infarction (29% vs. 7% P < 0.01), bleeding complications (27% vs. 7% P < 0.01), and hospital stay duration (11 +/- 11 vs. 8 +/- 5 days P < 0.05) decreased. Our data suggest that coronary stent implantation is currently an effective stand-alone bailout procedure for a large majority of failed angioplasty procedures.

In-hospital monitoring after coronary angioplasty.

At the University Hospital of Geneva there are three postcoronary angioplasty monitoring levels: (A) intensive care unit; (B) optional ECG monitoring (cardiology unit); and (C) no monitoring (other unit). To assess the adequacy of patient monitoring after coronary angioplasty, we studied the clinical outcome of 200 consecutive patients undergoing coronary angioplasty at different monitoring levels. Thirty-nine patients (20%) were in level A. Their outcome was 1 death, 1 emergency bypass operation, and 7 acute myocardial infarcts. Ninety-six patients (48%) were in level B: no major complication, no transfer of monitoring level, and mean hospital stay 2.7 +/- 1.3 days. Sixty-five patients (32%) were in level C: 1 death, 2 elective bypass operations, 6 transfers to level A, and mean hospital stay 5.9 +/- 4.6 days. Electrocardiogram monitoring of 135 patients yielded 23 significant findings (17%), 22 of which occurred in patients with complicated or failed procedure. In the 122 patients with successful coronary angioplasty without angiographic visible local complications and without clinical symptoms at the end of the procedure, no significant arrhythmia or acute myocardial infarction was documented. For this type of patient, ECG monitoring is not a prerequisite after coronary angioplasty. Surveying all patients after coronary angioplasty in the coronary care unit would not significantly reduce complications. Aftercare in a cardiology unit results in a shorter hospital stay.