Association between tissue loss type and amputation risk among Medicare patients with concomitant diabetes and peripheral arterial disease.

OBJECTIVE: Prior studies have described risk factors associated with amputation in patients with concomitant diabetes and peripheral arterial disease(DM/PAD). However, the association between the severity and extent of tissue loss type and amputation risk remains less well-described. We aimed to quantify the role of different tissue loss types in amputation risk among patients with DM/PAD, in the context of demographic, preventive, and socioeconomic factors. METHODS: Applying ICD-9 and ICD-10 codes to Medicare claims data(2007-2019), we identified all patients with continuous fee-for-service Medicare coverage diagnosed with DM/PAD. Eight tissue loss categories were established using ICD-9 and ICD-10 diagnosis codes, ranging from lymphadenitis(least severe) to gangrene(most severe). We created a Cox proportional hazards model to quantify associations between tissue loss type and one- and five-year amputation risk, adjusting for age, race/ethnicity, sex, rurality, income, comorbidities, and preventive factors. Regional variation in DM/PAD rates and risk-adjusted amputation rates was examined at the hospital referral region(HRR) level. RESULTS: We identified 12,257,174 patients with DM/PAD(48% male, 76% White, 10% prior myocardial infarction, 30% chronic kidney disease). While 2.2 million patients(18%) had some form of tissue loss, 10.0 million patients(82%) did not. The one-year crude amputation rate(major and minor) was 6.4% in patients with tissue loss, and 0.4% in patients without tissue loss. Among patients with tissue loss, one-year any amputation rate varied from 0.89% for patients with lymphadenitis to 26% for patients with gangrene. One-year amputation risk varied from two-fold for patients with lymphadenitis(aHR 1.96, 95%CI 1.43-2.69) to 29-fold for patients with gangrene(aHR 28.7, 95%CI 28.1-29.3), compared to patients without tissue loss. No other demographic variable including age, sex, race, or region incurred a hazard ratio for one- or five-year amputation risk higher than the least severe tissue loss category. Results were similar across minor and major amputation, and one- and five-year amputation outcomes. At a regional level, higher DM/PAD rates were inversely correlated with risk-adjusted five-year amputation rates(R2=0.43). CONCLUSION: Among 12 million patients with DM/PAD, the most significant predictor of amputation was presence and extent of tissue loss, with an association greater in effect size than any other factor studied. Tissue loss could be used in awareness campaigns as a simple marker of high-risk patients. Patients with any type of tissue loss require expedited wound care, revascularization as appropriate, and infection management to avoid amputation. Establishing systems of care to provide these interventions in regions with high amputation rates may prove beneficial for these populations.

Most preoperative stress tests fail to comply with practice guideline indications and do not reduce cardiac events.

BACKGROUND: There is wide variation in stress test utilization before major vascular surgery and adherence to practice guidelines is unclear. We defined rates of stress test compliance at our institution and led a quality improvement initiative to improve compliance with American Heart Association (ACC/AHA) guidelines. METHODS: We implemented a stress testing order set in the electronic medical record at one tertiary hospital. We reviewed all patients who underwent elective, major vascular surgery in the 6 months before (Jan 1, 2022 - Jul 1, 2022) and 6 months after (Aug 1, 2022 - Jan 31, 2023) implementation. We studied stress test guideline compliance, changes in medical or surgical management, and major adverse cardiac events (MACE). RESULTS: Before order set implementation, 37/122 patients (30%) underwent stress testing within the past year (29 specifically ordered preoperatively) with 66% (19/29) guideline compliance. After order set implementation, 50/173 patients (29%) underwent stress testing within the past year (41 specifically ordered preoperatively) with 80% (33/41) guideline compliance. In the pre- and postimplementation cohorts, stress testing led to a cardiovascular medication change or preoperative coronary revascularization in 24% (7/29) and 27% (11/41) of patients, and a staged surgery or less invasive anesthetic strategy in 14% (4/29) and 4.9% (2/41) of patients, respectively. All unindicated stress tests were surgeon-ordered and none led to a change in management. There was no change in MACE after order set implementation. CONCLUSIONS: Electronic medical record-based guidance of perioperative stress testing led to a slight decrease in overall stress testing and an increase in guideline-compliant testing. Our study highlights a need for improved preoperative cardiovascular risk assessment prior to major vascular surgery, which may eliminate unnecessary testing and more effectively guide perioperative decision-making.

The financial burden associated with endovascular repair of thoracoabdominal and pararenal aortic aneurysms using physician-modified fenestrated-branched endografts.

OBJECTIVE/BACKGROUND: Endovascular thoracoabdominal and pararenal aortic aneurysm repair is more complex and requires more devices than infrarenal aneurysm repair. It is unclear if current reimbursement covers the cost of delivering this more advanced form of vascular care. The objective of this study was to evaluate the economics of fenestrated-branched (FB-EVAR) physician-modified endograft (PMEG) repairs. METHODS: We obtained technical and professional cost and revenue data for four consecutive fiscal years (July 1, 2017, to June 30, 2021) at our quaternary referral institution. Inclusion criteria were patients who underwent PMEG FB-EVAR in a uniform fashion by a single surgeon for thoracoabdominal/pararenal aortic aneurysms. Patients in industry-sponsored clinical trials or receiving Cook Zenith Fenestrated grafts were excluded. Financial data were analyzed for the index operation. Technical costs were divided into direct costs that included devices and billable supplies and indirect costs including overhead. RESULTS: 62 patients (79% male, mean age: 74 years, 66% thoracoabdominal aneurysms) met inclusion criteria. The mean aneurysm size was 6.0 cm, the mean total operating time was 219 minutes, and the median hospital length of stay was 2 days. PMEGs were created with a mean number of 3.7 fenestrations, using a mean of 8.6 implantable devices per case. The average technical cost per case was $71,198, and the average technical reimbursement was $57,642, providing a net negative technical margin of $13,556 per case. Of this cohort, 31 patients (50%) were insured by Medicare remunerated under diagnosis-related group code 268/269. Their respective average technical reimbursement was $41,293, with a mean negative margin of $22,989 per case, with similar findings for professional costs. The primary driver of technical cost was implantable devices, accounting for 77% of total technical cost per case over the study period. The total operating margin, including technical and professional cost and revenue, for the cohort during the study period was negative $1,560,422. CONCLUSIONS: PMEG FB-EVAR for pararenal/thoracoabdominal aortic aneurysms produces a substantially negative operating margin for the index operation driven largely by device costs. Device cost alone already exceeds total technical revenue and presents an opportunity for cost reduction. In addition, increased reimbursement for FB-EVAR, especially among Medicare beneficiaries, will be important to facilitate patient access to such innovative technology.

The financial implications of cardiac stress testing prior to abdominal aortic aneurysm repair.

BACKGROUND: The utilization and cost-effectiveness of stress testing before abdominal aortic aneurysm (AAA) repair remains insufficiently studied. We examined the variation and financial implications of stress testing, and their association with major adverse cardiovascular events (MACE). METHODS: We studied patients who underwent elective endovascular (EVAR) or open AAA repair (OAR) at Vascular Quality Initiative centers from 2015 to 2019. We grouped centers into quintiles of preoperative stress testing frequency. We calculated the risk of postoperative MACE, a composite of in-hospital myocardial infarction, heart failure, or death, for each center-quintile. We obtained charges for stress tests locally and applied these to the cohort to estimate charges per 1000 patients. RESULTS: We studied 32,459 patients (EVAR: 27,978; OAR: 4481; 283 centers). Stress test utilization varied across quintiles from 13.0% to 68.6% (median: 36.8%) before EVAR and 15.9% to 85.0% (median: 59.4%) before OAR. The risk of MACE was 1.4% after EVAR and 10.2% after OAR. There was a trend towards more common MACE after EVAR among centers with higher utilization of stress testing: 0.9% among centers in the lowest quintile, versus 1.7% in the highest quintile (p-trend = 0.068). There was no association between MACE and stress testing frequency for OAR (p-trend = 0.223). The estimated financial charges for stress testing before EVAR ranged from $125,806 per 1000 patients at 1st-quintile centers, to $665,975 at 5th-quintile centers. Charges before OAR ranged from $153,861 at 1st-quintile centers, to $825,473 at 5th-quintile centers. CONCLUSION: Stress test use before AAA repair is highly variable and associated with substantial cost, with an unclear association with postoperative MACE. This highlights the need for improved stress testing paradigms prior to surgery.

Outcomes of rotational atherectomy in complex lesions of the superficial femoral artery.

BACKGROUND: The effectiveness of rotational atherectomy in the treatment of complex superficial femoral artery (SFA) lesions remains poorly defined. Outcomes of SFA lesions treated with rotational atherectomy were analyzed. METHODS: This retrospective review assessed all patients who underwent rotational atherectomy of the SFA at a single institution between 2015 and 2018. The data of all patients were deidentified, and the study was approved by the Institutional Review Board. Informed consent was not obtained for this retrospective analysis. Main outcomes were Kaplan-Meier primary patency rate, freedom from major amputation, and 2-year survival rate. The effect of drug-coated balloon angioplasty (DCBA) on patency and time to death was investigated with univariate regression. The safety profile for atherectomy and DCBA was assessed by the 30-day incidence of major amputation and all-cause mortality. RESULTS: Fifty-three patients (mean age, 70.2 ± 9.8 years; 73% male; 65% critical limb-threatening ischemia; 47 [90%] current or former smokers; seven [13%] with prior failed ipsilateral endovascular intervention) underwent rotational atherectomy (Jetstream; Boston Scientific, Marlborough, Mass) with mean follow-up of 543 days. Forty-six (87%) patients underwent DCBA (Lutonix; BD Bard, Covington, Ga) after atherectomy. Mean lesion length was 13.2 ± 9.0 cm. Thirty-one (58%) lesions were TransAtlantic Inter-Society Consensus C or D class. At 1-month follow-up, 39 of 45 (87%) patients experienced improvement in symptoms and Rutherford class. An improvement in ankle-brachial index was also noted in 13% of patients without improvement of symptoms, with no patients progressing to surgical bypass or major amputation. Mean ankle-brachial index increased from 0.54 ± 0.035 to 0.90 ± 0.031 at 1 month after intervention (P < .001) and remained constant out to 18 months. Mean toe pressure increased from 36 ± 3.8 mm Hg to 67 ± 4.5 mm Hg at 1 month after intervention (P < .001) and remained constant out to 18 months. Kaplan-Meier primary patency rate was 75% (95% confidence interval, 61%-85%) at 12 months and 65% (51%-77%) at 24 months. There was a trend toward improved primary patency after adjunctive DCBA compared with plain balloon angioplasty at 1 year (75% vs 43%; P = .1082). There was no significant difference in mortality between adjunctive DCBA and plain balloon angioplasty at 2 years (11% vs 0%). The 2-year incidence of major amputation in critical limb-threatening ischemia patients was 3.9% (1.2%-6.5%). One patient died and none underwent amputation within 30 days. CONCLUSIONS: Rotational atherectomy with adjunctive DCBA of long SFA lesions has excellent long-term patency. Two-year major amputation and mortality rates are low, and the technique has an exceptional safety profile.

Long-Term Outcomes of Mesenteric Stenting and Analysis of In-Stent Restenosis Duplex Velocity Criteria.

BACKGROUND: Endovascular therapy for chronic mesenteric ischemia (CMI) is the mainstay of treatment. Duplex velocity criteria within stented mesenteric vessels are not well established. We describe single-center outcomes of mesenteric stenting for CMI and analyze duplex velocities associated with in-stent restenosis (ISR). METHODS: We performed a single-center retrospective review of patients undergoing mesenteric stenting for CMI (2012-2018). Primary outcome was reintervention for recurrence of CMI symptoms. Secondary outcomes were occlusion or bypass grafting. Duplex velocities in those with recurrent symptoms, corresponding with clinically significant ISR, were identified. Receiver operating characteristic (ROC) curves were created to identify velocity thresholds for ISR. RESULTS: Mesenteric stents were placed in 61 patients (71 arteries). Mean age was 72 years (range, 49-92), and the majority were female (55%). Thirty-two (45%) celiac (CA) stents and 39 (55%) superior mesenteric artery (SMA) stents were placed. Ten patients had SMA and CA stents placed. Twenty-five stents were covered (35%). Freedom from reintervention at 1, 2, and 3 years was 83%, 73%, and 60%. Freedom from occlusion or bypass grafting at 1, 2, and 3 years was 100%, 86%, and 86%. No significant difference in patency was seen between covered and bare-metal stents (OR 0.45; 95% CI: 0.15-1.33; P = 0.1383). Median survival was 6.1 years. For CA stents, a peak systolic velocity (PSV) of 440 cm/s corresponded with clinically significant ISR with 100% sensitivity and 86% specificity. For SMA stents, a PSV of 341 cm/s corresponded with clinically significant ISR with only 80% sensitivity and 52% specificity. CONCLUSIONS: A PSV of 440 cm/s for CA stents was indicative of clinically significant ISR with excellent sensitivity and specificity. This should be used in conjunction with clinical findings to identify patients that may benefit from repeat intervention. A similar threshold could not be identified for SMA stents and warrants further collaborative investigation.

Laser assisted trans-endograft coil embolization of a type II endoleak.

A type II endoleak after endovascular aneurysm repair can be challenging to stop. Numerous methods have been described, including trans-arterial, trans-lumbar, trans-caval, trans-endograft, peri-endograft, and open and laparoscopic surgical techniques. We present our experience with a laser-assisted trans-endograft approach, including technical variations of previous descriptions that might improve efficacy. In select cases, the laser-assisted trans-endograft approach might provide the most direct method of accessing and occluding the vessels feeding type II endoleaks.

Postoperative Clostridium difficile infection has a differential procedure-specific association with surgical outcomes in contemporary United States practice.

BACKGROUND: The Centers for Disease Control and Prevention has made the prevention of in-hospital Clostridium difficile infection a priority. However, whether there is a differential impact of Clostridium difficile on surgical patients remains undefined. Therefore, we quantified the procedure-specific association between postoperative Clostridium difficile and surgical outcomes to define opportunities for targeted quality improvement. METHODS: We studied patients undergoing major cardiac, vascular, general, or oncologic procedures using the Vizient database from 2015 to 2019. Our primary exposure was postoperative Clostridium difficile infection. Our primary outcomes were postoperative length of stay, hospitalization cost, readmission, and in-hospital mortality. We used linear and logistic regression for risk adjustment. RESULTS: The incidence of Clostridium difficile infection was 1.6% (n = 6,506/397,750). Patients with Clostridium difficile were older, more comorbid, and more frequently underwent urgent surgery. The median postoperative length of stay was 7 days (interquartile range: 5-11 days), and it was 66% longer among those with Clostridium difficile (P < .001). Similarly, the median hospitalization cost was $31,000 (interquartile range: $20,000-$49,000), and it was 51% greater among patients with Clostridium difficile (P < .001). Postoperative Clostridium difficile was associated with more readmissions after coronary artery bypass grafting, small bowel resection, colectomy, gastrectomy, pancreatectomy, and infrainguinal bypass (adjusted odds ratio range: 1.4-1.7), but not after open aneurysm repair, suprainguinal bypass, or esophagectomy. Clostridium difficile was associated with increased mortality after coronary artery bypass grafting, small bowel resection, colectomy, and infrainguinal bypass (adjusted odds ratio range: 1.3-2.7), but not after open aneurysm repair, suprainguinal bypass, esophagectomy, gastrectomy, or pancreatectomy. CONCLUSION: Postoperative Clostridium difficile infection was differentially associated with increased length of stay, cost, readmissions, and mortality across specific procedures. This was most apparent after infrainguinal bypass, small bowel resection, colectomy, and coronary artery bypass grafting. Accordingly, a targeted Clostridium difficile reduction effort for these procedures may offer a more effective approach toward reducing infection rates.

Characterization of Ciprofloxacin Resistance Levels: Implications for Ototopical Therapy.

HYPOTHESIS: Ciprofloxacin-resistant pathogens are inhibited by high concentrations of ciprofloxacin found in commercially-available ototopical solutions. BACKGROUND: Ciprofloxacin-resistant pathogens in otitis media are currently treated with ototopical ciprofloxacin suspensions. This is done irrespective of laboratory-reported ciprofloxacin susceptibility, under the assumption that the high concentration of ciprofloxacin applied topically is sufficient to overcome antimicrobial resistance. METHODS: We evaluated 34 ciprofloxacin-resistant isolates consisting of Staphylococcus aureus, Pseudomonas aeruginosa, Corynebacterium spp., and Turicella otitidis. Ciprofloxacin minimum inhibitory concentration (MIC) assays and clinical ototopical solution minimum bactericidal concentration (CMBC) assays were performed. RESULTS: Amongst the ciprofloxacin-resistant isolates, ciprofloxacin MICs ranged from 8 to 256 mcg/ml (mean: 87.1 mcg/ml) and CMBCs ranged from 23.4 to 1500 mcg/ml (mean: 237.0 mcg/ml). There were no significant differences with respect to MIC in comparing P. aeruginosa versus Corynebacterium spp. (mean: 53.3 versus 55.2, p = 0.86), S. aureus versus P. aeruginosa (mean: 128.0 versus 53.3, p = 0.34), and S. aureus versus Corynebacterium spp. (mean: 128.0 versus 55.2, p = 0.09). The correlation between ciprofloxacin MIC and CMBC was poor (Pearson's r = -0.08, p = 0.75). CONCLUSIONS: Ciprofloxacin-resistant pathogens commonly recovered from otitis media exhibit highly variable ciprofloxacin MIC and CMBC levels. Ciprofloxacin was able to inhibit growth in all isolates tested at MIC levels less than or equal to 256 mcg/ml; however, CMBC's up to 1500 mcg/ml were observed within that same group. The clinical relevance of these in vitro MICs is unclear due in part to higher bactericidal concentrations (CMBC) in several strains. Our results suggest that treatment failures may be due to a combination of factors rather than high-level resistance alone.

A System for Characterizing Intraoperative Force Distribution During Operative Laryngoscopy.

OBJECTIVE: This study aimed to create and validate an integrated data acquisition system for gauging the force distribution between a laryngoscope and soft-tissue during trans-oral surgery. METHODS: Sixteen piezoresistive force sensors were interfaced to a laryngoscope and custom maxillary tooth guard. A protocol for calibrating the laryngoscope and maxilla sensors was developed using a motor-controlled linear stage and force measurements were validated against a digital scale. The system was initially tested during suspension laryngoscopy on three cadaver heads mounted on a cadaver head-holder. Intraoperative data was also collected from three patients undergoing head and neck tumor resection. RESULTS: Mean calibration error of the scope sensors was less than 150 g (n = 3) and mean maxilla sensor error was less than 200 g (n = 3). Peak scope mag-forces of 8.09 ± 6.61 kg and peak maxilla forces of 7.62 ± 4.57 kg were experienced during the cadaver trials. The peak scope sensor mag-force recorded during the intraoperative cases was 24.7 ± 4.53 kg, and the peak maxilla force was 22.0 ± 4.60 kg. CONCLUSION: The data acquisition system was successfully able to record intraoperative force distribution data. The usefulness of this technology in informing surgeons during trans-oral surgery should be further evaluated in patients with varying anatomic and procedural characteristics. SIGNIFICANCE: Creation of a low-cost, integrated force-sensing system allows for the characterization of retraction forces at anatomic sites including the pharynx and larynx, brain, and abdomen. Real-time force detection provides surgeons with valuable intraoperative feedback and can be used to improve deformation models at various anatomic sites.

Multi-modal Framework for Image-guided Trans-oral Surgery with Intraoperative Imaging and Deformation Modeling.

Treatment of throat cancers have improved due to minimally-invasive trans-oral approaches. Surgeons rely on preoperative imaging to guide their resection; however, large tissue deformations occur during trans-oral procedures due to placement of necessary retractors and laryngoscopes which hinders the surgeon's ability to accurately assess tumor extent and location of critical structures. We propose an image-guided framework utilizing intraoperative imaging and deformation modeling to improve surgeon accuracy and confidence. A CT-compatible laryngoscopy system previously developed was evaluated in this framework. Intraoperative images were acquired during laryngoscopy; force-sensing capabilities were enabled in the laryngoscope; and tracking of the scope and anatomic features was trialed. Tissue deformation and displacement were quantified and determined to be extensive, with values <; 4.6 cm in the tongue, <; 1.8 cm in bony structures, and <; 108.9 cm3 in airway volume change. Surgical navigation using intraoperative imaging and tracking was evaluated. Preliminary assessment of deformation modeling showed potential to supplement intraoperative imaging. Future work will involve streamlined integration of the components of this framework.