Percutaneous Transluminal Coronary Angioplasty Treatment Research Articles

Quasi-experimental evidence on the effectiveness of heart attack treatment in Germany

ABSTRACT Medical technological progress has been shown to be the main driver of health care costs. A key policy question is whether new treatment options are worth the additional costs. In this analysis we assess the causal effect of percutaneous transluminal coronary angioplasty (PTCA), a major new heart attack treatment, on mortality. We use a full sample of administrative hospital data from Germany for the years 2005 to 2007. To account for non-random treatment assignment of PTCA, instrumental variable approaches are implemented that aim to randomize patients into getting PTCA independent of heart attack severity. Instruments include differential distances to PTCA hospitals and regional PTCA rates. Our results suggest a 4.5 absolute percentage point mortality reduction for patients who have access to PTCA compared to patients receiving only conservative treatment. We relate mortality reduction to the additional costs for this treatment and conclude that PTCA treatment is cost-effective in lowering mortality for AMI patients at reasonable cost-effectiveness thresholds.

Avβ3 Single-Stranded DNA Aptamer Attenuates Vascular Smooth Muscle Cell Proliferation and Migration via Ras-PI3K/MAPK Pathway.

Objectives To observe the effect of avβ3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism. Background Percutaneous transluminal coronary angioplasty (PTCA) is currently the preferred method for the treatment of coronary heart disease. However, vascular restenosis still occurs after PTCA treatment, severely affecting the clinical efficacy of PTCA. Integrin avβ3, which is widely expressed on various cell surfaces, plays an important role in the proliferation and migration of VSMCs. Methods In this experiment, we used systematic evolution of ligands by exponential enrichment (SELEX) to screen out avβ3 ssDNA, which has high affinity and specificity to the avβ3 protein. MTT, Transwell, and cell scratch assays were carried out to examine the effect of avβ3 ssDNA on the proliferation and migration of VSMCs. Flow cytometry was performed to detect apoptosis and cell cycle progression. The effect of avβ3 ssDNA on the Ras-phosphatidylinositol-4,5-bisphosphate 3-kinase/mitogen-activated protein kinase (PI3K/MAPK) signaling pathway was evaluated by quantitative reverse transcription polymerase chain reaction and western blot. Results In the present study, we found that avβ3 ssDNA significantly decreased the expression of osteopontin, focal adhesion kinase, Ras, p-PI3K, and p-MAPK at both mRNA and protein levels (P < 0.05). Avβ3 ssDNA also inhibited VSMC proliferation and migration while promoting apoptosis (P < 0.05), as demonstrated by the upregulation of the proapoptotic proteins Bax and active caspase 3 (P < 0.05). Conclusions The findings suggest that avβ3 ssDNA inhibited the proliferation and migration of VSMCs by suppressing the activation of Ras-PI3K/MAPK signaling.

Acute myocardial infarction: does pre-hospital treatment increase survival?

The aim of this study was to assess the impact of a mobile emergency care unit (MECU) staffed with an anaesthetist, in terms of increased survival among patients with acute myocardial infarction (MI). The setting was an urban area with 330 000 inhabitants. This was a quasi-experimental before-and-after-study including consecutive emergency calls during September to November 1996 (Period 1, without the MECU) and September to November 1997 (Period 2, including the MECU). Fifty-four ambulance patients had their MI diagnosis confirmed at hospital during Period 1, and another 54 in Period 2. The 28-day mortality was collected from relevant registers. Twenty-four (44%) of Period 2 patients were transported by the MECU. MECU patients had lower systolic blood pressure (SBP) than other patients, both before and after hospital admission. Nitroglycerine treatment was relatively frequent in MECU patients, and cardioversion, anaesthesia and intubation was applied exclusively in these patients. After arrival at hospital, MECU patients had thrombolysis relatively often (46% versus 23% in other Period 2 patients) but percutaneous transluminal coronary angioplasty (PTCA) relatively infrequently (21% vs 30%). The total mortality was significantly lower in Period 2 than in Period 1 patients (11% vs 21%, <0.025), irrespective of differences in the distribution of age, gender, pulse and SBP, measured at hospital. Also, the more specific MECU use, alone and in combination with subsequent PTCA treatment, was found to be associated with prolonged survival. Pre-hospital treatment by an MECU staffed by an anaesthetist and/or having a PTCA seems to be associated with prolonged survival in acute MI patients. It must be underscored that these observations have been based on quasi-experimental rather than randomized experimental data.

BOLD-MRI in ten patients with coronary artery disease: evidence for imaging of capillary recruitment in myocardium supplied by the stenotic artery.

Changes of myocardial oxygenation can be studied by measurements of the apparent transverse relaxation time T2*, which is correlated with the oxygenation state of hemoglobin. In this study, ten patients with coronary artery disease (CAD) underwent blood oxygenation level dependent (BOLD) T2* measurements using a segmented gradient echo pulse sequence with ten echoes. T2* measurements were performed in a single short-axis slice of the heart at rest and under pharmacological stress with dipyridamole (DIP), which increases myocardial blood flow. For comparison, all patients underwent X-ray angiography and stress-echocardiography within 4 days after the MR exam. In one patient, MR examination was repeated 10 weeks after percutaneous transluminal coronary angioplasty (PTA). In the differential T2* maps, expected ischemic areas of myocardium were identified in six patients. In these regions, T2+ values (30 +/- 8 ms) were significantly reduced when compared to the remaining myocardium (48 +/- 9 ms, P < 0.01). In four patients, the myocardial region of interest could not be assessed owing to severe susceptibility artifacts in the ischemic region. The success of the PTA treatment could be visualized from a more homogeneous DIP induced increase in T2* within the ischemic myocardium (from 26 +/- 1 to 29 +/- 1 ms before PTA versus 26 +/- 1 to 31 +/- 4 ms after PTA, P < 0.001).

BOLD-MRI in ten patients with coronary artery disease: evidence for imaging of capillary recruitment in myocardium supplied by the stenotic artery

Changes of myocardial oxygenation can be studied by measurements of the apparent transverse relaxation time T2*, which is correlated with the oxygenation state of hemoglobin. In this study, ten patients with coronary artery disease (CAD) underwent blood oxygenation level dependent (BOLD) T2* measurements using a segmented gradient echo pulse sequence with ten echoes. T2* measurements were performed in a single short-axis slice of the heart at rest and under pharmacological stress with dipyridamole (DIP), which increases myocardial blood flow. For comparison, all patients underwent X-ray angiography and stress-echocardiography within 4 days after the MR exam. In one patient, MR examination was repeated 10 weeks after percutaneous transluminal coronary angioplasty (PTA). In the differential T2* maps, expected ischemic areas of myocardium were identified in six patients. In these regions, T2* values (30±8 ms) were significantly reduced when compared to the remaining myocardium (48±9 ms, P<0.01). In four patients, the myocardial region of interest could not be assessed owing to severe susceptibility artifacts in the ischemic region. The success of the PTA treatment could be visualized from a more homogeneous DIP induced increase in T2* within the ischemic myocardium (from 26±1 to 29±1 ms before PTA versus 26±1 to 31±4 ms after PTA, P<0.001).

Prospective Study of Extraction Atherectomy in Patients With Acute Myocardial Infarction

Although percutaneous transluminal coronary angioplasty (PTCA) has been an effective treatment for primary reperfusion in acute myocardial infarction, patients with thrombolytic ineligibility, thrombolytic failure, cardiogenic shock, and vein graft occlusion remain at high risk for complications with PTCA treatment. The transluminal extraction catheter may be useful for treatment of such patients owing to its ability to aspirate thrombus. At 2 clinical centers, extraction atherectomy was prospectively evaluated in 100 patients (age 62 ± 10 years). High-risk features included thrombolytic failure in 40%, postinfarct angina in 28%, presence of angiographic thrombus in 66%, presence of cardiogenic shock in 11%, and a saphenous vein graft occlusion in 29%. Procedural success, defined as a final residual stenosis <50% and Thrombolysis in Myocardial Infarction 2 or 3 grade flow, was seen in 94%. Events during the hospitalization included death in 5%, bypass surgery in 4%, and blood transfusion in 18%. In a substudy, patients enrolled at William Beaumont Hospital (n = 65) underwent elective predischarge angiography, which revealed a patent infarct-related vessel in 95%. These patients were also followed for 6 months with angiographic follow-up in 60%. Target vessel revascularization was necessary in 38%, and 6-month mortality was 10%. Although long-term vessel patency was 90%, angiographic restonosis occurred in 68%. Acute myocardial infarction patients can be treated with extraction atherectomy with a high technical success rate and a low week and 6 months was excellent; however, angiographic restenosis remains a problem. Extraction of thrombus in this high-risk group of patients is associated with low in-hospital mortality and a high rate of vessel patency at 6 months.

Effects of direct percutaneous transluminal coronary angioplasty treatment of acute myocardial infarction on plasma levels of haemostatic and fibrinolytic factors

Although thrombolytic therapy is used widely for treatment of acute myocardial infarction (AMI), thrombolysis itself increases thrombin activity and may cause reocclusion of infarct-related vessels. Direct percutaneous transluminal coronary angioplasty (PTCA) is an effective treatment for AMI; however, it is not clear what effects PTCA has on coagulation and fibrinolysis. We investigated coagulation and fibrinolytic factor concentrations before and after direct PTCA. Plasma levels of thrombin-antithrombin III complex (TAT), D-dimer, plasmin-(alpha 2-antiplasmin complex (PAP), tissue-type plasminogen activator (t-PA) antigen and plasminogen activator inhibitor (PAI)-1 antigen were followed in twelve patients treated with direct PTCA for AMI. Before PTCA, only TAT concentrations were significantly elevated compared to normal controls. D-dimer, TAT, PAP and PAI-1 concentrations were similar before and after PTCA. Eleven patients had no recurrent ischaemia and no restenosis on follow-up coronary angiography. These data confirm that direct PTCA is less likely than thrombolysis to affect coagulation and fibrinolysis.

Effects of direct percutaneous transluminal coronary angioplasty treatment of acute myocardial infarction on plasma levels of haemostatic and fibrinolytic factors

Although thrombolytic therapy is used widely for treatment of acute myocardial infarction (AMI), thrombolysis itself increases thrombin activity and may cause reocclusion of infarct-related vessels. Direct percutaneous transluminal coronary angioplasty (PTCA) is an effective treatment for AMI; however, it is not clear what effects PTCA has on coagulation and fibrinolysis. We investigated coagulation and fibrinolytic factor concentrations before and after direct PTCA. Plasma levels of thrombin-antithrombin III complex (TAT), D-dimer, plasmin-(α2-antiplasmin complex (PAP), tissue-type plasminogen activator (t-PA) antigen and plasminogen activator inhibitor (PAI)-1 antigen were followed in twelve patients treated with direct PTCA for AMI. Before PTCA, only TAT concentrations were significantly elevated compared to normal controls. D-dimer, TAT, PAP and PAI-1 concentrations were similar before and after PTCA. Eleven patients had no recurrent ischaemia and no restenosis on follow-up coronary angiography. These data confirm that direct PTCA is less likely than thrombolysis to affect coagulation and fibrinolysis.