P. Michael Grossman

Use of a Constitutively Active Hypoxia-Inducible Factor-1α Transgene as a Therapeutic Strategy in No-Option Critical Limb Ischemia Patients Phase I Dose-Escalation Experience

Background— Critical limb ischemia, a manifestation of severe peripheral atherosclerosis and compromised lower-extremity blood flow, results in a high rate of limb loss. We hypothesized that adenoviral delivery of a constitutively active form of the transcription factor hypoxia-inducible factor-1&agr; (ie, Ad2/HIF-1&agr;/VP16 or HIF-1&agr;) into the lower extremity of patients with critical limb ischemia would be safe and might result in a durable clinical response. Methods and Results— This phase I dose-escalation program included 2 studies: a randomized, double-blind, placebo-controlled study and an open-label extension study. In total, 34 no-option patients with critical limb ischemia received HIF-1&agr; at doses of 1×108 to 2×1011 viral particles. No serious adverse events were attributable to study treatment. Five deaths occurred: 3 in HIF-1&agr; and 2 in placebo patients. In the first (randomized) study, 7 of 21 HIF-1&agr; patients met treatment failure criteria and had major amputations. Three of the 7 placebo patients rolled over to receive HIF-1&agr; in the extension study. No amputations occurred in the 2 highest-dose groups of Ad2/HIF-1&agr;/VP16 (1×1011 and 2×1011 viral particles). The most common adverse events included peripheral edema, disease progression, and peripheral ischemia. At 1 year, limb status observations in HIF-1&agr; patients included complete rest pain resolution in 14 of 32 patients and complete ulcer healing in 5 of 18 patients. Conclusions— HIF-1&agr; therapy in patients with critical limb ischemia was well tolerated, supporting further, larger, randomized efficacy trials.

Incomplete retention after direct myocardial injection.

Direct intramyocardial injection may permit local delivery of protein and gene therapy agents for myocardial and coronary artery disease. Little is known about the immediate fate of materials administered via percutaneous endomyocardial catheters or via surgical epicardial injection. In this study, we use a novel method to evaluate the acute retention of agents injected directly into the myocardium, compare epicardial with the percutaneous endocardial and postmortem delivery, and evaluate the influence of injectate volume on myocardial retention. Fifteen 40–50 kg pigs underwent overlapping myocardial injections using a percutaneous endomyocardial catheter, an epicardial needle via an open chest, and epicardial needle postmortem. Multiple distinct 15 μ neutron‐activated microsphere species were used as tracers. Two or three myocardial walls were injected in each animal using 3.5 mm, 27–28 gauge needles at varying injectate volumes. Animals were sacrificed immediately. Myocardial walls were divided and multiple microsphere species were quantified. In an additional study, nine 70 kg pigs underwent percutaneous endomyocardial injections with replication‐deficient adenovirus encoding for the production of lac‐Z. The injectate volume was varied, while the viral particle number remained constant. The animals were sacrificed 5 days after the percutaneous injections; the heart, liver, and spleen were collected for β‐galactosidase activity. Endomyocardial injection was associated with 43% ± 15% microsphere retention, compared with 15% ± 21% (P < 0.01) retention of open chest epicardial injection and 89% ± 60% (P < 0.01) for postmortem injection. Reducing the injectate volume from 100 to 10 μL improved microsphere retention (P = 0.01). There was a trend toward improved viral transfection associated with smaller injection volumes. Despite direct intramyocardial administration, a significant fraction of injectate is not retained locally. Catheter‐based needle endomyocardial injection is associated with equivalent or superior injectate retention compared with open chest epicardial injection. Proportionately, more injectate may be retained at lower volumes. Loss may involve a combination of channel leakage, venous, and lymphatic return. Cathet Cardiovasc Intervent 2002;55:392–397.

Missed opportunities to treat atherosclerosis in patients undergoing peripheral vascular interventions: Insights from the University of Michigan peripheral vascular disease quality improvement initiative (PVD-QI2)

Background—Peripheral vascular disease is a manifestation of systemic atherosclerosis and is associated with an increased risk of cardiovascular morbidity and mortality. Methods and Results—We examined clinical outcomes in 66 consecutive patients undergoing peripheral vascular interventions at our institution between January 2001 and October 2001. At hospital discharge and at 6 months, lifestyle modifications and use of evidence-based therapy was suboptimal. At 6 months, a significant proportion continued to smoke (22.7%) and only half of the patients exercised, controlled their weight, or modified their diet for lipid control. The use of antiplatelet therapy was 77.2%; of angiotensin-converting enzyme, 35.9%; of &bgr;-blockers, 42.5%; and of statins, 50%. Twelve of the 66 patients (18.2%) had a clinical event of death, myocardial infarction, or stroke. An appropriateness algorithm for use of secondary prevention measures was created with the use of evidence-based therapy guidelines, and a composite appropriateness variable was also created. The use of evidence-based therapy was associated with a significant reduction of the composite of death, myocardial infarction, and stroke at 6 months (OR 0.02, 95% CI 0.01 to 0.44, P =0.01). Conclusions—Atherosclerosis risk factors are very prevalent in patients with peripheral vascular disease, but these patients receive less than optimal treatment after a predominantly technical vascular intervention. Effective secondary prevention with appropriate lifestyle interventions and evidence-based medical therapy needs to be strongly encouraged and implemented in these patients.

Current role of sodium bicarbonate-based preprocedural hydration for the prevention of contrast-induced acute kidney injury: a meta-analysis.

BACKGROUND The optimal hydration strategy for prevention of contrast-induced acute kidney injury (AKI) remains unknown. The purpose of this meta-analysis is to compare the effectiveness of normal saline (NS) versus sodium bicarbonate hydration (NaHCO(3)) for prevention of contrast-induced AKI. METHODS We performed a meta-analysis of randomized controlled trials that compared saline-based hydration with sodium bicarbonate-based hydration regimen for prophylaxis of contrast-induced AKI. The literature search included MEDLINE, EMBASE, and Cochrane databases (2000 to October 2007); conference proceedings; and bibliographies of retrieved articles. Information was extracted on study design, sample characteristics, and interventions. Random-effects models were used to calculate summary risk ratios for contrast-induced AKI, need for hemodialysis, and death. RESULTS Seven trials with 1,307 subjects were included. Preprocedural hydration with sodium bicarbonate was associated with a significant decrease in the rate of contrast-induced AKI (5.96% in the NaHCO(3) arm versus 17.23% in the NS arm, summary risk ratio 0.37, 95% CI 0.18-0.714, P = .005). There was no difference in the rates of postprocedure hemodialysis or death. Formal testing revealed moderate heterogeneity and a strong likelihood of publication bias. CONCLUSIONS Although sodium bicarbonate hydration was found to be superior to NS in prevention of contrast-induced AKI, these results are in the context of study heterogeneity and, likely, publication bias. An adequately powered randomized controlled trial is warranted to define the optimal hydration strategy in patients at high risk of contrast-induced AKI who are scheduled to undergo contrast administration.

Safety and efficacy of thrombectomy in patients undergoing primary percutaneous coronary intervention for Acute ST elevation MI: A Meta-Analysis of Randomized Controlled Trials

BackgroundClinical trials comparing thrombectomy devices with conventional percutaneous coronary interventions (PCI) in patients with acute ST elevation myocardial infarction (STEMI) have produced conflicting results. The objective of our study was to systematically evaluate currently available data comparing thrombectomy followed by PCI with conventional PCI alone in patients with acute STEMI.MethodsSeventeen randomized trials (n = 3,909 patients) of thrombectomy versus PCI were included in this meta-analysis. We calculated the summary odds ratios for mortality, stroke, post procedural myocardial blush grade (MBG), thrombolysis in myocardial infarction (TIMI) grade flow, and post procedural ST segment resolution (STR) using random-effects and fixed-effects models.ResultsThere was no difference in risk of 30-day mortality (44/1914 vs. 50/1907, OR 0.84, 95% CI 0.54-1.29, P = 0.42) among patients randomized to thrombectomy, compared with conventional PCI. Thrombectomy was associated with a significantly greater likelihood of TIMI 3 flow (1616/1826 vs. 1533/1806, OR 1.41, P = 0.007), MBG 3 (730/1526 vs. 486/1513, OR 2.42, P < 0.001), STR (923/1500 vs. 715/1494, OR 2.30, P < 0.001), and with a higher risk of stroke (14/1403 vs. 3/1413, OR 2.88, 95% CI 1.06-7.85, P = 0.04). Outcomes differed significantly between different device classes with a trend towards lower mortality with manual aspiration thrombectomy (MAT) (21/949 vs.36/953, OR 0.59, 95% CI 0.35-1.01, P = 0.05), whereas mechanical devices showed a trend towards higher mortality (20/416 vs.10/418, OR 2.07, 95% CI 0.95-4.48, P = 0.07).ConclusionsThrombectomy devices appear to improve markers of myocardial perfusion in patients undergoing primary PCI, with no difference in overall 30-day mortality but an increased likelihood of stroke. The clinical benefits of thrombectomy appear to be influenced by the device type with a trend towards survival benefit with MAT and worsening outcome with mechanical devices.

The changing definition of contrast-induced nephropathy and its clinical implications: Insights from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2)

BACKGROUND The traditional definition of contrast-induced nephropathy (CIN) has been an absolute rise of serum creatinine (Cr) of ≥0.5 mg/dL, although most recent clinical trials have included a ≥25% increase from baseline Cr. The clinical implication of this definition change remains unknown. METHODS AND RESULTS We compared the association of the two definitions with risk of death or need for dialysis among 58,957 patients undergoing percutaneous coronary intervention in 2007 to 2008 in a large collaborative registry. Patients with a preexisting history of renal failure requiring dialysis were excluded. Contrast-induced nephropathy as defined by a rise in Cr ≥0.5 mg/dL (CIN(Traditional)) developed in 1,601, whereas CIN defined either as Cr ≥0.5 mg/dL or ≥25% increase in baseline Cr (CIN(New)) developed in 4,308 patients. Patients meeting the definition of CIN(New) but not CIN(Traditional) were classified as CIN(Incremental) (n = 2,707). Compared with CIN(New), CIN(Traditional) was more commonly seen in patients with abnormal renal function, which was more likely to develop in patients with normal renal function at baseline. Compared with CIN(Incremental), patients meeting the definition of CIN(Traditional) were more likely to die (16.7% vs 1.7%) and require in-hospital dialysis (9.8% vs 0%). CONCLUSIONS Our data suggest that the traditional definition of CIN (a rise in Cr of ≥0.5 mg/dL) in patients undergoing PCI is superior to ≥25% increase in Cr at identifying patients at greater risk for adverse renal and cardiac events.

Psoas muscle size as a frailty measure for open and transcatheter aortic valve replacement

OBJECTIVE To evaluate the use of sarcopenia as a frailty assessment tool for patients with aortic stenosis undergoing surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR). METHODS The study cohort comprised 295 patients who underwent either SAVR (n = 156) or TAVR (n = 139). The mean preoperative Society of Thoracic Surgeons mortality risk score was 4.7%. Preoperative computed tomography (CT) scans were used to calculate gender-standardized total psoas area (TPA), as a validated measure of sarcopenia. RESULTS For the entire cohort, independent predictors of a composite measure of 30-day death, stroke, renal failure, prolonged ventilation, and deep wound infection included preoperative STS major morbidity and mortality risk score (odds ratio [OR], 91.1; P = .02) and TPA (OR, 0.5; P = .024). Two-year survival was 85.7% in patients with sarcopenia, compared with 93.8% in patients without sarcopenia (P = .02). Independent predictors of late survival included TPA (hazard ratio, 0.47; P = .02). Male sex (OR, 0.52; P = .04) and TPA (OR, 0.6; P = .001) were predictive of high resource utilization. A separate analysis by treatment group found that TPA predicted high resource utilization after SAVR (OR, 0.4; P < .001), but not after TAVR (P = .66). CONCLUSIONS CT scan-derived measurement of TPA as an objective frailty assessment tool predicts early morbidity and mortality, high resource utilization, and late survival after treatment for aortic stenosis. The correlation observed between sarcopenia and resource utilization after SAVR versus TAVR suggests that this simple and reproducible risk assessment tool also may help identify those patients who will derive optimal benefit from catheter-based therapy.

Compared with control subjects, the systemic sympathetic nervous system is activated in patients with mitral regurgitation

BACKGROUND Whether the systemic sympathetic nervous system is activated as a compensatory mechanism in response to mitral regurgitation (MR) in humans is unknown. We tested the hypotheses that the systemic sympathetic nervous system would be activated in patients with MR in comparison with control subjects and that this activation would occur early in the disease process as a compensatory mechanism for chronic left ventricular (LV) volume overload. METHODS We studied 37 patients with MR who underwent right heart catheterization and biplane cineventriculography to obtain LV end-diastolic and end-systolic volumes, ejection fractions, and regurgitant volumes. In these 37 patients with MR and in 23 control subjects, an [(3)H]-norepinephrine ([(3)H]-NE) infusion and multiple arterial blood samples provided data for a 2-compartment modeling analysis to calculate extravascular NE release rates (NE(2)). RESULTS The mean NE(2) (2.05 +/- 0.76 microg/min/m(2)) in the patients with MR was greater than that in the control subjects (1.48 +/- 0.75 microg/min/m(2), P =.007). Furthermore, the mean NE(2) values were also greater in the patients with MR who were in clinical class I (P =.05), with a pulmonary capillary wedge pressure <12 mm Hg (P =.05) or a LV ejection fraction >or=0.60 (P =.06) compared with the control subjects. The mean NE(2) values were increased further in patients with MR who had a LV ejection fraction <0.60 (P =.02). CONCLUSIONS The systemic sympathetic nervous system is activated in patients with MR in comparison with control subjects, and this activation appears to occur early in the disease process as a compensatory mechanism for LV volume overload.

The Quality and Impact of Risk Factor Control in Patients With Stable Claudication Presenting for Peripheral Vascular Interventions

Background—Peripheral arterial disease is a manifestation of systemic atherosclerosis and is predictive of future cardiovascular events. Clinical trial data have demonstrated that medical therapy can attenuate cardiovascular morbidity and mortality in patients with peripheral arterial disease. The utilization and impact of recommended medical therapy in a contemporary population of patients who undergo percutaneous interventions for lifestyle-limiting peripheral arterial disease is unknown. Methods and Results—Using the Blue Cross Blue Shield of Michigan Cardiovascular Consortium Peripheral Vascular Intervention (BMC2 PVI) database, we identified 1357 peripheral vascular intervention encounters between January 2007 and December 2009 for the purpose of treating claudication. Before the intervention, 85% of these patients used aspirin, 76% used statin, 65% abstained from smoking, and 47% did all 3. There was no difference in cardiovascular events among those taking an aspirin and a statin on admission and those who were not. However, in both an unadjusted and a multivariable analysis, the odds of an adverse peripheral vascular outcome (repeat peripheral intervention, amputation, or limb salvage surgery) within 6 months decreased by more than half in patients receiving aspirin and statin therapy before peripheral vascular intervention as compared with those who received neither (odds ratio, 0.45; 95% CI, 0.29–0.71). Conclusions—The fundamental elements of medical therapy in patients with lifestyle-limiting claudication are often underutilized before referral for revascularization. Appropriate medical therapy before percutaneous revascularization is associated with fewer peripheral vascular events at 6 months.

Percutaneous Coronary Intervention Complications and Guide Catheter Size. Bigger Is Not Better

OBJECTIVES We evaluated the association between guiding catheter size and complications of percutaneous coronary intervention (PCI). BACKGROUND The association between guiding catheter size and complications of PCI in contemporary practice remains controversial. METHODS Procedure and outcome variables from 103,070 consecutive patients that underwent PCI with 6-F (n = 64,335), 7-F (n = 32,676), and 8-F (n = 6,059) guide catheters were compared. RESULTS Compared with 6-F guides, PCIs performed with 7- and 8-F guides were associated with incrementally more contrast agent use, and more post-PCI complications including contrast-induced nephropathy, vascular access site complications, bleeding, transfusion, major adverse cardiac event, and death. After multivariate analysis, the use of larger guides were associated with a higher risk of contrast-induced nephropathy (7-F odds ratio [OR]: 1.18, p = 0.0004; 8-F OR: 1.44, p < 0.0001), vascular complications (7-F OR: 1.19, p = 0.0002, 8-F OR: 1.68, p < 0.0001), decline in hemoglobin >3 g/dl (7-F OR: 1.12, p < 0.0001, 8-F OR: 1.72, p < 0.0001), and post-procedure blood transfusion (7-F OR: 1.08, p = 0.03; 8-F OR: 1.80, p < 0.0001), whereas major adverse cardiac events (7-F OR: 1.06, p = 0.13; 8-F OR: 1.37, p < 0.0001) and in-hospital mortality (7-F OR: 1.11, p = 0.13; 8-F OR: 1.34, p = 0.03) were increased with 8-F but not 7-F guides. CONCLUSIONS Compared with 6-F guides, PCIs performed with 7- and 8-F guides were associated with more contrast medium use, renal complications, bleeding, vascular access site complications, greater need for post-procedure transfusion, and 8-F guides with increased nephropathy requiring dialysis, in-hospital major adverse cardiac events, and mortality. These data suggest that selection of smaller guide catheters may result in improved clinical outcome in patients undergoing contemporary PCI.