Trends and outcomes of non-primary PCI at sites without cardiac surgery on-site: The early Michigan experience

Introduction

Non-primary percutaneous coronary intervention (non-PPCI) recently received certificate of need approval in the state of Michigan at sites without cardiac surgery on-site (cSoS). This requires quality oversight through participation in the BMC2 registry. While previous studies have indicated the safety of this practice, real-world comprehensive outcomes, case volume changes, economic impacts, and readmission rates at diverse healthcare centers with and without cSoS remain poorly understood.

Methods

Consecutive patients undergoing non-PPCI at 47 hospitals (33 cSoS and 14 non-cSoS) in Michigan from April 2016 to March 2018 were included. Using propensity-matching, patients were analyzed to assess outcomes and trends in non-PPCI performance at sites with and without cSOS.

Results

Of 61,864 PCI’s performed, 50,817 were non-PPCI, with 46,096 (90.7%) performed at sites with cSoS and 4,721 (9.3%) at sites without cSoS. From this cohort, 4,643 propensity-matched patients were analyzed. Rates of major adverse cardiac events (2.6% vs. 2.8%; p = 0.443), in-hospital mortality (0.6% vs. 0.5%; p = 0.465), and several secondary clinical and quality outcomes showed no clinically significant differences. Among a small subset with available post-discharge data, there were no differences in 90-day readmission rates, standardized episode costs, or post-discharge mortality. Overall PCI volume remained stable, with a near three-fold rise in non-PPCI at sites without cSoS.

Conclusions

Non-PPCI at centers without cardiac SoS was associated with similar comprehensive outcomes, quality of care, 90-day episode costs, and post-discharge mortality compared with surgical sites. Mandatory quality oversight serves to maintain appropriate equivalent outcomes and may be considered for other programs, including the performance of non-PPCI at ambulatory surgical centers in the near future.

Primary percutaneous coronary intervention at centers with and without on-site surgical support: Insights from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2)

BACKGROUND

Primary percutaneous coronary intervention (PPCI) is being increasingly performed nationally at sites without on-site cardiac surgery; however, recent guidelines only provide a Class IIa recommendation for this practice. The state of Michigan has permitted PPCI without on-site surgery under a closely monitored system that mandates auditing of all procedures and quarterly feedback on quality and outcomes. This study sought to compare outcomes of patients undergoing PPCI at centers with and without on-site surgery in the state of Michigan.

METHODS

Consecutive patients who underwent PPCI at 47 hospitals in Michigan from January 2010 to December 2015 were included. From this cohort, 4,091 patients from sites with and without on-site cardiac surgery were propensity matched in a 1:1 fashion to compare baseline characteristics, procedural details, and in-hospital outcomes.

RESULTS

Of the 25,886 PPCIs performed at 47 hospitals in Michigan from 2010 to 2015, 21,610 (83.5%) were performed at sites with on-site surgery and 4,276 (16.5%) at sites without on-site surgery. Using propensity score matched cohorts (4,091 patients for each site type), we found no significant differences in baseline characteristics. Overall mortality (5.4% vs 5.8%; P=.442); composite outcome of in-hospital mortality, contrast-induced nephropathy, bleeding, and stroke (13.8% vs 12.8%; P=.152); and individual outcomes within the composite group showed no significant differences. Additionally, there were no clinically meaningful differences in rates of urgent/emergent coronary artery bypass graft or length of stay. Significant differences, however, were found in procedural access site, antiplatelet therapy, contrast volume, and anticoagulant strategy.

CONCLUSIONS

Primary PCI performed at centers with and without cardiac surgery have comparable outcomes and complication rates when performed with close monitoring of quality and outcomes.

Single coronary ostium in right coronary sinus: previously unreported "one for all" configuration

We report our identification of a single coronary ostium arising from the right coronary sinus of Valsalva, in a 63-year-old woman who presented with chest pain atypical of angina. Coronary angiograms showed that the left anterior descending coronary artery arose from a right ventricular branch and that the left circumflex coronary artery arose from a right posterolateral branch. Both arteries reconstituted themselves in a backward fashion from the apex to the base of the heart-a configuration that to our knowledge has not been reported. The patient was treated conservatively and reported no chest pain 24 months later.

Comparison of clinical interpretation with visual assessment and quantitative coronary angiography in patients undergoing percutaneous coronary intervention in contemporary practice: the Assessing Angiography (A2) project

BACKGROUND

Studies conducted decades ago described substantial disagreement and errors in physicians' angiographic interpretation of coronary stenosis severity. Despite the potential implications of such findings, no large-scale efforts to measure or improve clinical interpretation were subsequently undertaken.

METHODS AND RESULTS

We compared clinical interpretation of stenosis severity in coronary lesions with an independent assessment using quantitative coronary angiography (QCA) in 175 randomly selected patients undergoing elective percutaneous coronary intervention at 7 US hospitals in 2011. To assess agreement, we calculated mean difference in percent diameter stenosis between clinical interpretation and QCA and a Cohen weighted κ statistic. Of 216 treated lesions, median percent diameter stenosis was 80.0% (quartiles 1 and 3, 80.0% and 90.0%), with 213 (98.6%) assessed as ≥70%. Mean difference in percent diameter stenosis between clinical interpretation and QCA was 8.2±8.4%, reflecting an average higher percent diameter stenosis by clinical interpretation (P<0.001). A weighted κ of 0.27 (95% confidence interval, 0.18-0.36) was found between the 2 measurements. Of 213 lesions considered ≥70% by clinical interpretation, 56 (26.3%) were <70% by QCA, although none were <50%. Differences between the 2 measurements were largest for intermediate lesions by QCA (50% to <70%), with variation existing across sites.

CONCLUSIONS

Physicians tended to assess coronary lesions treated with percutaneous coronary intervention as more severe than measurements by QCA. Almost all treated lesions were ≥70% by clinical interpretation, whereas approximately one quarter were <70% by QCA. These findings suggest opportunities to improve clinical interpretation of coronary angiography.

MT1-MMP-dependent remodeling of cardiac extracellular matrix structure and function following myocardial infarction

The myocardial extracellular matrix (ECM), an interwoven meshwork of proteins, glycoproteins, proteoglycans, and glycosaminoglycans that is dominated by polymeric fibrils of type I collagen, serves as the mechanical scaffold on which myocytes are arrayed for coordinated and synergistic force transduction. Following ischemic injury, cardiac ECM remodeling is initiated via localized proteolysis, the bulk of which has been assigned to matrix metalloproteinase (MMP) family members. Nevertheless, the key effector(s) of myocardial type I collagenolysis both in vitro and in vivo have remained unidentified. In this study, using cardiac explants from mice deficient in each of the major type I collagenolytic MMPs, including MMP-13, MMP-8, MMP-2, MMP-9, or MT1-MMP, we identify the membrane-anchored MMP, MT1-MMP, as the dominant collagenase that is operative within myocardial tissues in vitro. Extending these observations to an in vivo setting, mice heterozygous for an MT1-MMP-null allele display a distinct survival advantage and retain myocardial function relative to wild-type littermates in an experimental model of myocardial infarction, effects associated with preservation of the myocardial type I collagen network as a consequence of the decreased collagenolytic potential of cardiac fibroblasts. This study identifies MT1-MMP as a key MMP responsible for effecting postinfarction cardiac ECM remodeling and cardiac dysfunction.

Routine stent implantation vs. percutaneous transluminal angioplasty in femoropopliteal artery disease: a meta-analysis of randomized controlled trials

AIMS

We performed a meta-analysis of randomized controlled trials comparing routine stenting (ST) with percutaneous transluminal angioplasty (PTA) for symptomatic superficial femoral-popliteal artery (SFPA) disease.

METHODS AND RESULTS

Ten trials were pooled randomizing patients to ST (n = 724 limbs) or PTA with provisional stenting (n = 718 limbs) with a follow-up period of 9-24 months. The mean lesion length was similar in the two groups (45.8 mm in the ST group and 43.3 mm in the PTA group). We calculated the summary risk ratios (RRs) for immediate technical failure, restenosis, and target vessel revascularization (TVR) using random-effects models. The immediate technical failure was higher in the PTA group than in the ST group [17.1 vs. 5.9%, respectively, RR = 0.28, 95% confidence interval (CI) = 0.15-0.54, P < 0.001], with 10.3% of the PTA patients undergoing stenting because of suboptimal result. There was a trend for lower restenosis in the ST group (37.6% in ST vs. 45.3% in PTA, RR = 0.85, 95% CI = 0.69-1.06, P = 0.146), but no difference in the need for TVR (20% in ST vs. 20.2% in PTA, RR = 0.98, 95% CI = 0.78-1.23, P = 0.89). In an analysis restricted to nitinol stents, there was a trend towards reduction in TVR (RR = 0.79, 95% CI = 0.59-1.06, P = 0.12).

CONCLUSION

Despite the higher immediate success, routine stenting was not associated with a significant reduction in the rate of restenosis or TVR. Our data do not support use of routine stenting as the primary endovascular treatment for short SFPA lesions.

MT1-matrix metalloproteinase directs arterial wall invasion and neointima formation by vascular smooth muscle cells

During pathologic vessel remodeling, vascular smooth muscle cells (VSMCs) embedded within the collagen-rich matrix of the artery wall mobilize uncharacterized proteolytic systems to infiltrate the subendothelial space and generate neointimal lesions. Although the VSMC-derived serine proteinases, plasminogen activator and plasminogen, the cysteine proteinases, cathepsins L, S, and K, and the matrix metalloproteinases MMP-2 and MMP-9 have each been linked to pathologic matrix-remodeling states in vitro and in vivo, the role that these or other proteinases play in allowing VSMCs to negotiate the three-dimensional (3-D) cross-linked extracellular matrix of the arterial wall remains undefined. Herein, we demonstrate that VSMCs proteolytically remodel and invade collagenous barriers independently of plasmin, cathepsins L, S, or K, MMP-2, or MMP-9. Instead, we identify the membrane-anchored matrix metalloproteinase, MT1-MMP, as the key pericellular collagenolysin that controls the ability of VSMCs to degrade and infiltrate 3-D barriers of interstitial collagen, including the arterial wall. Furthermore, genetic deletion of the proteinase affords mice with a protected status against neointimal hyperplasia and lumen narrowing in vivo. These studies suggest that therapeutic interventions designed to target MT1-MMP could prove beneficial in a range of human vascular disease states associated with the destructive remodeling of the vessel wall extracellular matrix.

Local imbalance of proangiogenic and antiangiogenic factors: a potential mechanism of focal necrosis and dormancy in tumors

Solid tumors produce both stimulators and inhibitors of angiogenesis. The suppression of metastases by some primary tumors has been attributed to the longer circulatory half-lives of the inhibitors. We propose that intrinsic differences in the physicochemical properties of these regulators may also explain focal suppression of angiogenesis within the primary tumor. We present a mathematical framework that describes production, diffusion, and degradation of these factors in tumor and host tissue and their effect on angiogenesis at local and distal sites. Results show focal suppression of angiogenesis, provide an explanation for tumor dormancy and focal necrosis, and predict a suppressive influence of primary tumors on angiogenesis at metastatic sites. They suggest generally that diffusible factors produced by tumors can stimulate responses in adjacent host tissue, preparing it for further tumor invasion. This study presents a new paradigm for the development of tumor necrosis and offers new insight into angiogenesis regulation and therapy. The framework established for modeling the competing effects of diffusible stimulators and inhibitors can be applied more generally to growth factors/inhibitors and other opposing factors produced in the tumor environment.

During angiogenesis, vascular endothelial growth factor and basic fibroblast growth factor regulate natural killer cell adhesion to tumor endothelium

Localization of activated natural killer (A-NK) cells in the microvasculature of growing tumors is the result of recognition of the intracellular and vascular cell-adhesion molecules ICAM-1 and VCAM-1 on the tumor endothelium, mediated by lymphocyte function-associated protein LFA-1 and vascular lymphocyte function-associated protein VLA-4. In vitro and in vivo studies of A-NK cell adhesion to endothelial cells showed that vascular endothelial growth factor (VEGF) promotes adhesion, whereas basic fibroblast growth factor (bFGF) inhibits adhesion through the regulation of these molecules on tumor vasculature. Thus, some angiogenic factors may facilitate lymphocyte recognition of angiogenic vessels, whereas others may provide such vessels with a mechanism that protects them from cytotoxic lymphocytes.

Leukocyte-endothelial adhesion and angiogenesis in tumors

Leukocyte-endothelial adhesion and angiogenesis, until recently considered as separate processes, have been shown to be linked by two recent findings: soluble cellular adhesion molecules (CAMs) involved in leukocyte-endothelial interactions are angiogenic and well known angiogenic molecules secreted by cancer or immune. cells can modulate the endothelial CAMs. This molecular link may partially explain why the overall leukocyte-endothelial interaction is often low and heterogeneous in angiogenic tumor vessels and why activated lymphocytes adhere nonuniformly to tumor vessels when injected into the tumor's blood supply.

Adhesion of activated natural killer cells to tumor necrosis factor-alpha-treated endothelium under physiological flow conditions

Adhesion of activated natural killer (A-NK) cells to activated and nonactivated endothelial cells in vitro was studied under dynamic flow conditions. Endothelial cells grown on glass slides were either treated with tumor necrosis factor-alpha (TNF alpha) or medium, then placed into a flow chamber over which suspensions of A-NK cells were passed using a range of defined shear stress levels. Significant numbers of binding cells could be consistently observed at shear stress levels less than 3 dyn/cm2 on TNF alpha-activated endothelium or at 0.59 dyn/cm2 on nonactivated endothelium. Stable adhesion occurred rapidly following the initial interaction of the following cells with the endothelium in the absence of detectable rolling. Pretreatment of the A-NK cells with monoclonal antibodies directed against CD18 (LFA-1) or CD49d (VLA-4) resulted in a significant reduction in the number of binding cells. Simultaneous treatment with both monoclonal antibodies eliminated all A-NK adhesion occurring over 0.5 dyn/cm2. Pretreatment of the endothelial cells with antibodies against E- or P-selectin resulted in a small but significant reduction in binding only at 0.5 dyn/cm2. The binding efficiency of the A-NK cells was similar to that previously observed for T lymphocytes under the same conditions. Once bound, approximately half of the adherent cells could resist detachment when exposed to wall shear stresses over 12 dyn/cm2. These findings indicate that A-NK cell adhesion to activated endothelium can occur under shear stress conditions which are representative of postcapillary venules and that this binding is mediated principally by both CD18 and CD49d. A-NK cell adhesion also occurs to nonactivated endothelium but only at wall shear stress levels less than 1 dyn/cm2.

Kinetics of adhesion molecule expression and spatial organization using targeted sampling fluorometry

Cellular interactions with the vascular wall under flow conditions are controlled, in part, by the density of adhesion molecules on endothelial cells. The spatial arrangement and absolute levels of these molecules over the endothelium are therefore important determinants of cellular localization. Many biochemical and functional studies have characterized the interactions between leukocytes and endothelial monolayers, but no reliable method has been reported for quantifying the spatial expression of adhesion molecules on intact endothelial cell monolayers. We report the development of targeted sampling fluorometry (TSF), which uses standard immunostaining, fluorescence microscopy and digital image analysis techniques to analyze cell surface molecule expression on a cell-by-cell basis. This technique is performed on an intact monolayer and results in cellular intensity distributions that reflect spatial heterogeneity in adhesion molecule expression. We demonstrate the use of targeted sampling fluorometry in a study of the kinetics of tumor necrosis factor alpha-induced activation of human umbilical vein endothelial cell monolayers and show that the spatial patterns of adhesion molecule expression correlate with the locations of bound lymphocytes.