TGF-[beta]1 limits plaque growth, stabilizes plaque structure, and prevents aortic dilation in apolipoprotein E-null mice.

OBJECTIVE: Impairment of transforming growth factor (TGF)-beta1 signaling accelerates atherosclerosis in experimental mice. However, it is uncertain whether increased TGF-beta1 expression would retard atherosclerosis. The role of TGF-beta1 in aneurysm formation is also controversial. We tested whether overexpression of active TGF-beta1 in hyperlipidemic mice affects atherogenesis and aortic dilation. METHODS AND RESULTS: We generated apolipoprotein E-null mice with transgenes that allow regulated overexpression of active TGF-beta1 in their hearts. Compared to littermate controls, these mice had elevated cardiac and plasma TGF-beta1, less aortic root atherosclerosis (P< or =0.002), fewer lesions in the thoracic and abdominal aortae (P< or =0.01), less aortic root dilation (P<0.001), and fewer pseudoaneurysms (P=0.02). Mechanistic studies revealed no effect of TGF-beta1 overexpression on plasma lipids or cytokines, or on peripheral lymphoid organ cells. However, aortae of TGF-beta1-overexpressing mice had fewer T-lymphocytes, more collagen, less lipid, lower expression of inflammatory cytokines and matrix metalloproteinase-13, and higher expression of tissue inhibitor of metalloproteinase-2. CONCLUSIONS: When overexpressed in the heart and plasma, TGF-beta1 is an antiatherogenic, vasculoprotective cytokine that limits atherosclerosis and prevents aortic dilation. These actions are associated with significant changes in cellularity, collagen and lipid accumulation, and gene expression in the artery wall.

Mechanisms of TGF-beta1-induced intimal growth: plasminogen-independent activities of plasminogen activator inhibitor-1 and heterogeneous origin of intimal cells.

Transforming growth factor (TGF)-beta(1) is a potent stimulator of intimal growth. We showed previously that TGF-beta(1) stimulates intimal growth through early upregulation of plasminogen activator inhibitor-1 (PAI-1) and, subsequently, PAI-1-dependent increases in cell migration and matrix accumulation. We also showed that PAI-1 negatively regulates TGF-beta(1) expression in the artery wall. Here we use plasminogen-deficient mice to test whether TGF-beta(1)-stimulated, PAI-1-dependent intimal growth and PAI-1 suppression of TGF-beta(1) expression are mediated through inhibition of plasminogen activation by PAI-1. We also use lineage tracing to investigate the origin of cells in TGF-beta(1)-induced intimas. Surprisingly, both TGF-beta(1)-induced, PAI-1-dependent intimal growth and PAI-1 suppression of TGF-beta(1) expression are independent of plasminogen. Moreover, approximately 50% of cells that migrate into the intima of TGF-beta(1)-overexpressing arteries carry a smooth muscle lineage marker, <1% carry a bone marrow lineage marker, and the remaining cells carry neither marker. Therefore, PAI-1 stimulates intimal growth and suppresses TGF-beta(1) expression through activities other than inhibition of plasminogen activation. In addition, contrary to widely held models, our results do not support a role for plasmin (or thrombospondin) in TGF-beta(1) activation in the artery wall. Further identification of the molecular targets through which PAI-1 stimulates intimal formation and suppresses TGF-beta(1) expression in the artery wall may reveal new approaches for inhibiting intimal formation. Our studies also discount bone marrow as an important source from which TGF-beta(1) recruits intimal cells and suggest instead that TGF-beta(1) induces substantial cell migration either from the adventitia or from an extravascular, but nonhematopoietic source.

Outcomes of 1,090 consecutive, elective, nonselected percutaneous coronary interventions at a community hospital without onsite cardiac surgery.

We evaluated the efficacy and safety of elective percutaneous coronary intervention (PCI) at a hospital without onsite cardiac surgery. A growing number of hospitals without onsite cardiac surgery perform elective PCI. Few hospitals have reported outcomes, despite controversy surrounding this practice. From August 2003 to December 2005, 1,090 elective PCI were performed at Saint Luke's South Hospital (SLS), a hospital without onsite cardiac surgery, for which the referral center is the Mid America Heart Institute (MAHI). The elective PCI program used experienced interventionalists, technicians, and nurses; a tested helicopter transport protocol; a well-equipped catheterization laboratory; and a quality assurance process. Baseline characteristics, procedural success, and adverse clinical outcomes were compared. Observed frequencies of in-hospital death, a combined end point of Q-wave myocardial infarction (MI)/emergency coronary artery bypass grafting (CABG) surgery, and vascular complications were compared with prediction models. SLS, with lower risk characteristics than MAHI, had unadjusted frequencies of procedural success (93% vs 94%, p = NS), Q-wave MI (0.3% vs 0.3%, p = NS), emergency CABG surgery (0.2% vs 0.03%, p = 0.09), vascular complications (0.6% vs 0.6%, p = NS), and in-hospital death (0.1% vs 0.8%, p = 0.002) that compared favorably with MAHI. Two patients transferred from SLS to MAHI for emergency CABG surgery without adverse effects. Fewer in-hospital deaths and vascular complications were observed at SLS than predicted by models. In conclusion, favorable clinical outcomes were achieved for elective PCI at a hospital without onsite cardiac surgery that used strict program requirements.

Phospholipid transfer protein activity is associated with inflammatory markers in patients with cardiovascular disease.

Plasma phospholipid lipid transfer protein (PLTP) has several known key functions in lipoprotein metabolism. Recent studies suggest that it also may play a role in the inflammatory response. Inflammatory cell activity contributes to the development of atherosclerosis. To seek further evidence for the association of PLTP with inflammation, we studied the relationship between PLTP activity and five inflammatory markers [C-reactive protein (CRP), serum amyloid A (SAA), interleukin 6 (IL-6), white blood cells (WBC), and fibrinogen] in 93 patients with low HDL and cardiovascular disease (CVD). Plasma PLTP activity had the strongest correlation with CRP (r=0.332, P<0.001) followed by SAA (r=0.239, P=0.021). PLTP, CRP, and SAA were significantly associated with body mass index (BMI), insulin or glucose, apolipoprotein (apo) B, and/or apo E level (r=0.264-0.393, P<0.01). PLTP, SAA, and IL-6 also were associated with the concentration of HDL particles without apo A-II [Lp(A-I)](r=0.373-0.472, P<0.005, n=56), but not particles with apo A-II. Smoking was associated with increased PLTP activity, CRP, and WBC, and hypertension with increased PLTP activity. In linear models, CRP remained significantly associated with PLTP after adjustment of CVD risk factors and insulin resistance. Also, much of the variability of plasma PLTP activity was explained by CRP, BMI, Lp(A-I), smoking, glucose, and blood pressure. These findings show for the first time that plasma PLTP activity is associated positively with CRP in CVD, a state of chronic inflammation.

Utilization of distal embolic protection in saphenous vein graft interventions (an analysis of 19,546 patients in the American College of Cardiology-National Cardiovascular Data Registry).

In clinical trials, the use of a distal embolic protection device (EPD) during saphenous vein graft (SVG) percutaneous intervention (PCI) decreases the incidence of major adverse events. However, the frequency of EPD use during SVG PCI in clinical practice is unknown. We evaluated 19,546 SVG PCI procedures in the American College of Cardiology-National Cardiovascular Data Registry from January 1, 2004, through March 30, 2006. EPD use was the primary outcome. Univariate and multivariable analyses were used to assess for characteristics associated with EPD use and to determine the association between EPD use and 2 outcomes: no-reflow and in-hospital mortality. EPDs were used in 22% of patients who underwent SVG PCI. Characteristics independently associated with EPD use were age (odds ratio [OR] 1.04, p = 0.03), male gender (OR 1.12, p = 0.02), older grafts (p <0.001 for the group), longer lesions (OR 1.16, p <0.001), and American College of Cardiology/American Heart Association class C lesions (OR 1.41, p <0.001). Patients were less likely to receive an EPD if they had class <3 grade flow according to Thrombolysis in Myocardial Infarction classification (p <0.001) or previously treated lesions (OR 0.55, p <0.001). There was a weak correlation between annual hospital PCI volume and EPD use (r = 0.2, p <0.001). Nineteen percent of centers did not use EPDs and 41% used them in <10% of cases. EPD use was independently associated with a lower incidence of no-reflow (OR 0.68, p = 0.032), but not in-hospital mortality (1.0% vs 0.9%, p = NS). In conclusion, in current practice, EPDs are used in <25% of SVG PCI procedures.

Transforming growth factor beta 1 induces neointima formation through plasminogen activator inhibitor-1-dependent pathways.

OBJECTIVE: The mechanisms through which transforming growth factor (TGF)-beta1 promotes intimal growth, and the pathways through which TGF-beta1 expression is regulated in the artery wall, are incompletely understood. We used a mouse model to investigate mechanisms of TGF-beta1-induced intimal growth. METHODS AND RESULTS: Adenovirus-mediated overexpression of TGF-beta1 in uninjured carotid arteries of wild-type mice induced formation of a cellular and matrix-rich intima. Intimal growth appeared primarily due to cell migration and matrix accumulation, with only a negligible contribution from cell proliferation. Overexpression of TGF-beta1 also stimulated expression of plasminogen activator inhibitor type 1 (plasminogen activator inhibitor [PAI]-1) in the artery wall. To test the hypothesis that PAI-1 is a critical downstream mediator of TGF-beta1-induced intimal growth, we transduced carotid arteries of PAI-1-deficient (Serpine1(-/-)) mice with the TGF-beta1-expressing vector. Overexpression of TGF-beta1 in Serpine1(-/-) arteries did not increase intimal growth, matrix accumulation, cell migration, or proliferation. Moreover, TGF-beta1-transduced arteries of Serpine1(-/-) mice secreted 6- to 10-fold more TGF-beta1 than did arteries of wild-type mice that were infused with the same concentration of the TGF-beta1-expressing vector. CONCLUSIONS: PAI-1 is both a critical mediator of TGF-beta1-induced intimal growth and a key negative regulator of TGF-beta1 expression in the artery wall.

Comparison of procedural complications with versus without interventional cardiology fellows-in-training during contemporary percutaneous coronary intervention.

Despite increasing complexity of contemporary procedures at tertiary care hospitals, the relationship between interventional cardiology fellows-in-training (ICFITs) and complications of percutaneous coronary intervention (PCI) has not been reported. We compiled logbooks of 6 ICFITs at an academic hospital and evaluated patient and procedural characteristics of PCIs performed with and without presence of an ICFIT. The primary end point was the composite of all in-hospital PCI complications defined by the American College of Cardiology's National Cardiovascular Data Registry: (1) catheterization laboratory events such as no-reflow and dissection/perforation, (2) general clinical events such as stroke or cardiogenic shock, (3) vascular and bleeding complications, and (4) miscellaneous complications such as peak troponin or creatinine levels. Logistic regression adjusted for differences in measured confounders between patients treated with and without presence of an ICFIT. All analyses were repeated after excluding PCI for ST-elevation myocardial infarction. Of 2,605 PCI procedures at the academic hospital between July 2007 and April 2010, an ICFIT was present for 1,638 procedures (63%). Despite having worse clinical and procedural characteristics, patients in the ICFIT group experienced similar rates of the composite end point (12.9% vs 14.5% without ICFIT, p = 0.27). Longer mean fluoroscopy times and greater number of stents were noted in the ICFIT group; however, hospital length of stay was shorter and no individual adverse events were increased in the ICFIT procedures. Presence of an ICFIT remained unrelated to the composite end point after multivariable adjustment (odds ratio 0.92, 95% confidence interval 0.71 to 1.20; p = 0.53), and findings were similar after excluding PCI for ST-elevation myocardial infarction. In conclusion, in contemporary practice at a large academic medical center, PCI complication rates were not adversely affected by the presence of an ICFIT.

Drug-eluting stents and the use of percutaneous coronary intervention among patients with class I indications for coronary artery bypass surgery undergoing index revascularization: analysis from the NCDR (National Cardiovascular Data Registry).

OBJECTIVES: Our purpose was to evaluate percutaneous coronary intervention (PCI) attempt rates in patients with class I indications for coronary artery bypass graft (CABG) surgery after the introduction of drug-eluting stents (DES). BACKGROUND: In patients with severe, multivessel coronary disease, CABG has historically been recommended over PCI. Practice guidelines for CABG were last updated before the emergence of data on DES efficacy. METHODS: We analyzed 265,028 procedures from the NCDR (National Cardiovascular Data Registry) meeting American College of Cardiology/American Heart Association class I indications for surgical revascularization. Temporal trends in PCI attempt rates were analyzed during 3 consecutive time periods: pre-DES (before April 1, 2003), DES diffusion (April 1, 2003 to December 31, 2004), and DES (January 1, 2005 to September 30, 2006). RESULTS: The attempted rate of PCI in patients with class I indications for CABG increased over the 3 time periods (pre-DES: 29.4%, DES diffusion: 33.4%, and DES era: 34.7%, p < 0.001). In a hierarchical multivariable logistic model adjusting for patient and PCI site characteristics, PCI attempts were more likely in the DES compared with pre-DES era (odds ratio: 1.44, 95% confidence interval: 1.40 to 1.48) and the DES diffusion era (odds ratio: 1.20, 95% confidence interval: 1.17 to 1.23). PCI attempt rates increased in all 3 time periods, although the average rate of increase during the DES era was 0.6% per quarter compared with 0.3% per quarter for both the DES diffusion and the pre-DES eras (p = 0.03). CONCLUSIONS: DES use in clinical practice was associated with a significant overall increase in PCI to treat patients with class I indications for CABG. Long-term follow-up of this cohort of patients is warranted.

Bleeding in patients undergoing percutaneous coronary intervention: the development of a clinical risk algorithm from the National Cardiovascular Data Registry.

BACKGROUND: Bleeding in patients undergoing percutaneous coronary intervention (PCI) is associated with increased morbidity, mortality, length of hospitalization, and cost. We identified baseline clinical characteristics associated with bleeding complications after PCI and developed a simplified, clinically useful algorithm to predict patient risk. METHODS AND RESULTS: Data were analyzed from 302 152 PCI procedures performed at 440 US centers participating in the National Cardiovascular Data Registry. As defined by the National Cardiovascular Data Registry, bleeding required transfusion, prolonged hospital stay, and/or a drop in hemoglobin >3.0 g/dL from any location, including percutaneous entry site, retroperitoneal, gastrointestinal, genitourinary, and other/unknown location. Bleeding complications occurred in 2.4% of patients. From the best-fitting model consisting of 15 clinical elements associated with post-PCI bleeding in a random 80% training cohort, we developed a parsimonious risk algorithm. Predictors of bleeding included age, gender, previous heart failure, glomerular filtration rate, peripheral vascular disease, no previous PCI, New York Heart Association/Canadian Cardiovascular Society Functional Classification class IV heart failure, ST-elevation myocardial infarction, non-ST-elevation myocardial infarction, and cardiogenic shock. The parsimonious model was validated in the remaining 20% of the population (c-statistic, 0.72) and in clinically relevant subgroups of patients. This simplified model was used to derive a clinical risk algorithm, with larger numbers corresponding with greater risk. In 3 categories, bleeding rates were greater in patients with higher estimates (or=18, 5.1%). CONCLUSIONS: This report identifies baseline clinical factors associated with bleeding and proposes a clinically useful algorithm to estimate bleeding risk. This model is potentially actionable in altering therapeutic decision making and improving outcomes in patients undergoing PCI.

Intravascular ultrasound measures of coronary atherosclerosis are associated with the Framingham risk score: an analysis from a global IVUS registry.

AIMS: In addition to an adjunctive imaging platform during coronary angiography, intravascular ultrasound (IVUS) with Virtual Histology (VH) is increasingly being used to quantify coronary atherosclerosis. The relationship between VH-IVUS measures of coronary atherosclerosis and traditional cardiovascular risk factors has not been completely described. The objective of this study was to determine if an association exists between VH-IVUS measures of coronary atherosclerosis and the Framingham risk score in a prospective, multinational registry. METHODS AND RESULTS: Patients enrolled from 2004-2006 at 37 multinational centres in the prospective VHIVUS Global Registry were analysed. All subjects underwent diagnostic coronary angiography followed by IVUS. A Framingham risk score (FRS) was calculated for each subject, then stratified into three exclusive estimates (<10%, 10-19%, or >or= 20%) for future coronary heart disease (CHD) event risk over 10 years. Among 531 patients, plaque volume of the most diseased 10 mm segment increased with increasing FRS (P=0.006, adjusted for multiple comparisons). Patients with higher FRS estimates of CHD risk had a higher proportion of plaque classified as thin cap fibroatheroma compared with patients in the middle and lower risk score categories (21.4% vs 15.2% and 11.3%, respectively, P=0.008, adjusted for multiple comparisons). CONCLUSIONS: Using data from a large, multinational VH-IVUS registry we describe an association between the Framingham risk score and VH-IVUS measures of atherosclerosis within the most diseased 10 mm segment, namely plaque volume and the proportion of thin cap fibroatheroma.

Suitability of saphenous vein graft lesions for the use of distal embolic protection devices.

The use of distal embolic protection devices (EPD) in saphenous vein graft percutaneous interventions (SVG-PCI) has been associated with a decrease in adverse events. Currently, there are limited data regarding the percentage of SVG lesions that are suitable for EPD deployment. We retrospectively reviewed 131 SVG-PCI procedures occurring over 18 months for suitability for EPD deployment, utilizing previously published suitability criteria. We found that 49% of cases were suitable for EPD use, which is similar to results from other studies. Given the data supporting the use of EPD use in SVG-PCI, we feel that these findings should motivate interventional operators to establish benchmark standards for employing EPDs to improve the care of patients undergoing SVG-PCI.

Intravascular ultrasound radiofrequency analysis of coronary atherosclerosis: an emerging technology for the assessment of vulnerable plaque.

Evaluation of atherosclerotic plaque composition and morphometry may yield insight into plaque biology and the mechanisms of plaque-associated thrombosis. Analysis of intravascular ultrasound radiofrequency (IVUS-RF) backscatter signal is one technology that provides in vivo assessment of both atherosclerotic plaque composition and morphometry. We summarize three different approaches to IVUS-RF and critique the studies using this technology. In addition, we address the potential application of IVUS-RF to assess vulnerable plaque.

In vivo expression of a conditional TGF-beta1 transgene: no evidence for TGF-beta1 transgene expression in SM22alpha-tTA transgenic mice.

Transforming growth beta-1 (TGF-beta1) appears to play a critical role in the regulation of arterial intimal growth and the development of atherosclerosis. TGF-beta1 is expressed at increased levels in diseased arteries; however, its role in disease development remains controversial. Experiments in which TGF-beta1 is overexpressed in the artery wall of transgenic mice could clarify the role of TGF-beta1 in the development or prevention of vascular disease. However, constitutive overexpression of a TGF-beta1 transgene in the mouse artery wall is embryonically lethal. Therefore, to overexpress TGF-beta1 in the artery wall of adult mice, we generated mice that were transgenic for a conditional, tetracycline operator (tetO)-driven TGF-beta1 allele. These mice were viable, and when crossed with mice expressing a tetracycline-regulated transactivator (tTA) in the heart, expressed the TGF-beta1 transgene in a cardiac-restricted and doxycycline-dependent manner. Nevertheless, breeding of the tetO-TGF-beta1 transgene into three lines of mice transgenic for a smooth muscle-targeted tTA (SM22alpha-tTA mice; reported elsewhere to transactivate tetO-driven alleles in smooth muscle cells of large arteries) did not yield expression of the TGF-beta1 transgene. Moreover, tTA expression was not detected in aortae of the SM22alpha-tTA mice. Transgenic mice that express tTA at high levels in vascular smooth muscle and reliably transactivate tetO-driven transgenes would be useful for deciphering the role of TGF-beta1 (or other proteins) in normal arterial physiology and in the development of arterial disease. Currently available SM22alpha-tTA mice were not useful for this purpose. Generation of higher-expressing lines of SM22alpha-tTA mice appears warranted.

A critical developmental role for tgfbr2 in myogenic cell lineages is revealed in mice expressing SM22-Cre, not SMMHC-Cre.

Smooth muscle cell (SMC)-specific deletion of transforming growth factor beta (TGF-beta) signaling would help elucidate the mechanisms through which TGF-beta signaling contributes to vascular development and disease. We attempted to generate mice with SMC-specific deletion of TGF-beta signaling by mating mice with a conditional ("floxed") allele for the type II TGF-beta receptor (tgfbr2flox) to mice with SMC-targeted expression of Cre recombinase. We bred male mice transgenic for smooth muscle myosin heavy chain (SMMHC)-Cre with females carrying tgfbr2flox. Surprisingly, SMMHC-Cre mice recombined tgfbr2flox at low levels in SMC and at high levels in the testis. Recombination of tgfbr2flox in testis correlated with high-level expression of SMMHC-Cre in testis and germline transmission of tgfbr2null. In contrast, mice expressing Cre from a SM22alpha promoter (SM22-Cre) efficiently recombined tgfbr2flox in vascular and visceral SMC and the heart, but not in testis. Use of the R26R reporter allele confirmed that Cre-mediated recombination in vascular SMC was inefficient for SMMHC-Cre mice and highly efficient for SM22-Cre mice. Breedings that introduced the SM22-Cre allele into tgfbr2flox/flox zygotes in order to generate adult mice that are hemizygous for SM22-Cre and homozygous for tgfbr2flox- and would have conversion of tgfbr2flox/flox to tgfbr2null/null in SMC-produced no live SM22-Cre : tgfbr2flox/flox pups (P<0.001). We conclude: (1) "SMC-targeted" Cre lines vary significantly in specificity and efficiency of Cre expression; (2) TGF-beta signaling in the subset of cells that express SM22alpha is required for normal development; (3) generation of adult mice with absent TGF-beta signaling in SMC remains a challenge.