Postoperative acute kidney injury following intraoperative blood product transfusions during cardiac surgery.

INTRODUCTION: This study explored the nature of the association between intraoperative usage of red blood cell, fresh frozen plasma, cryoprecipitate or platelet transfusions and acute kidney injury. METHODS: A total of 1175 patients who underwent cardiac surgery between 2008 and 2013 were retrospectively analyzed. We assessed the association between: (1) preoperative patient characteristics and acute kidney injury, (2) intraoperative blood product usage and acute kidney injury, (3) acute kidney injury and 30-day mortality or re-hospitalization. RESULTS: In our cohort of 1175 patients, 288 patients (24.5%) developed acute kidney injury. This included 162 (13.8%), 69 (5.9%) and 57 (4.9%) developing stage 1, stage 2 or stage 3 acute kidney injury, respectively. Increased red blood cell, fresh frozen plasma or platelet transfusions increased the odds of developing acute kidney injury. Specifically, every unit of red blood cells, fresh frozen plasma or platelets transfused was associated with an increase in the covariate-adjusted odds ratio of developing ⩾ stage 2 kidney injury of 1.18, 1.19 and 1.04, respectively. CONCLUSIONS: Intraoperative blood product transfusions were independently associated with an increased odds of developing acute kidney injury following cardiac surgery. Further randomized studies are needed to better define intraoperative transfusion criteria.

Pathology of balloon-expandable and self-expanding stents following MRI-guided transapical aortic valve replacement.

BACKGROUND AND AIM OF THE STUDY: Balloon-expandable (BE) and self-expanding (SE) prostheses are both used for transcatheter aortic valve replacement (TAVR), but differences in long-term outcome using these types of device are unknown. The study aim was to monitor the histopathology, echocardiographic findings and structural integrity of BE and SE stents in a preclinical model for up to six months after TAVR. METHODS: Real-time magnetic resonance imaging (rtMRI)-guided TAVR was performed in 22 Yucatan pigs using either a BE (n = 10) or a SE (n = 12) prosthesis. Follow up echocardiography and MRI studies were performed at one-, three-, and six-month intervals. Additionally, high-contrast radiography was used to assess for strut fractures. The pigs were sacrificed after six months and tissues taken for histopathologic analysis. RESULTS: Stent malapposition was found in seven BE prostheses (70%), and in three SE prostheses (25%) (p = 0.046). Three of the SE group (25%) had a partial left coronary artery obstruction. The incidence and severity of aortic regurgitation were similar between the BE and SE groups. Three BE prostheses (30%) and one SE prosthesis (8.3%) had a gap between the stent frame and aorta. The mean (±SD) number of strut fractures was 6.1 ± 3.45 and 1.17 ± 2.32 in the BE and SE groups, respectively (p = 0.002). In addition, two implanted BE prostheses (20%) had a consequential compressed stent frame appearance. CONCLUSION: Long-term pathologic examination of necropsy specimens from a preclinical model of rtMRI-guided TAVR showed SE stent prostheses to be superior to their BE counterparts in terms of correct valve apposition and durability. These results may be attributed to the differing deployment methods and associated expansion forces employed by the BE and SE stents.

Aortic Regurgitation, Time to Aortic Valve Reintervention, and Mortality in Degenerated Trifecta Versus Non-Trifecta Bioprosthesis.

On July 31, 2023, the Trifecta valve was withdrawn from the market after concerns regarding early (≤5 years) structural valve deterioration (SVD), mainly as aortic regurgitation (AR). Our aim was to determine the timing, mechanism, and impact of bioprosthetic SVD in patients who underwent redo aortic valve replacement (redo-AVR) with either redo-SAVR or valve-in-valve transcatheter aortic valve replacement (TAVR) using Trifecta versus other bioprosthetic valves. Patients who underwent redo-AVR for SVD at our institution were categorized into 2 groups based on the valve type: Trifecta versus non-Trifecta. Multivariate Cox proportional hazard model and Kaplan-Meier curves were used to compare mortality. A total of 171 patients were included; 58 (34%) had previous SAVR with a Trifecta valve and 113 (66%) with non-Trifecta valve. A total of 103 patients (60%) underwent valve-in-valve TAVR and 68 redo-SAVR (40%). The age, gender, and Society of Thoracic Surgeons score were similar between Trifecta and non-Trifecta groups. In patients with bioprosthetic valves requiring redo-AVR, Trifecta valves had an earlier onset of greater than moderate AR (4.5 vs 11.9 years, p <0.001) and earlier time to redo-AVR (5.5 vs 12 years, p <0.001). AR was more common as the mechanism of SVD in Trifecta versus non-Trifecta valves (55.2% vs 30.1%, p = 0.006). All-cause adjusted mortality from index SAVR was higher in the Trifecta than in non-Trifecta group (hazard ratio 4.1, 95% confidence interval 1.5 to 11.5, p = 0.007). In conclusion, compared with non-Trifecta valves, Trifecta valves exhibit early SVD primarily as AR and progress rapidly to significant SVD requiring redo-AVR. Mortality is significantly higher with Trifecta than in non-Trifecta valves, potentially impacting the results of SAVR versus TAVR studies.

Heart Transplant Using a Donor Heart With Only a Persistent Left Superior Vena Cava: A Case Report.

A persistent left superior vena cava (PLSVC) is a congenital anomaly wherein the left superior cardinal vein fails to regress. We describe the case of a successful orthotopic heart transplant using a donor heart with a PLSVC and congenital absence of a right superior vena cava (SVC) in a recipient with normal anatomy. After donor cardiectomy, the donor organ's PLSVC was ligated near the insertion site into the coronary sinus. The recipient underwent cardiectomy such that the native SVC was left with a long right atrial cuff. A modified bicaval technique was used to anastomose the recipient's right atrial cuff directly to the donor's right atrial appendage. This technique restored the recipient's normal anatomy, and we demonstrated that donor hearts with a PLSVC and absent right SVC might be used for transplant. Without other disqualifying abnormalities, surgeons should consider accepting these organs for life-saving transplant operations.

Multidisciplinary Approach to Isolated Pulmonary Vein Compression by an Enlarging Vertebral Osteophyte.

Compression of mediastinal structures by vertebral osteophytes is rare. We report a case of pulmonary vein compression by a vertebral osteophyte that failed stenting. A minimally invasive approach to osteophyte removal with subsequent re-expansion angioplasty yielded an optimal outcome, negating the need for cardiopulmonary bypass, stent removal, and pulmonary venoplasty. (Level of Difficulty: Intermediate.).

Modern practice and outcomes of reoperative cardiac surgery.

OBJECTIVES: To evaluate recent practice and outcomes of reoperative cardiac surgery via re-sternotomy. Use of early versus late institution of cardiopulmonary bypass (CPB) before sternal re-entry was of particular interest. METHODS: From January 2008 to July 2017, 7640 patients underwent reoperative cardiac surgery at Cleveland Clinic. The study group consisted of 6627 who had a re-sternotomy and preoperative computed tomography scans; 755 and 5872 were in the early and late institution of CPB groups, respectively. Patients were stratified into high (n = 563) or low (n = 6064) anatomic risk of re-entry on the basis of computed tomography criteria. Weighted propensity-balanced operative mortality and morbidity were compared with surgeon as a random effect. RESULTS: Reoperative procedures most commonly incorporated aortic valve replacement (n = 3611) and coronary artery bypass grafting (n = 2029), but also aortic root (n = 1061) and arch procedures (n = 527). Unadjusted operative mortality was 3.5% (235/6627), and major sternal re-entry and mediastinal dissection injuries were uncommon (2.8%). In the propensity-weighted analysis, similar mortality (3.1% vs 4.5%; P = .6) and major morbidity, including stroke (1.8% vs 3.2%) and dialysis (0 vs 2.6%), were noted in the high anatomic risk cohort between early and late CPB groups. Similar trends were observed in the low anatomic risk cohort (mortality 3.5% vs 2.1%; P = .2). CONCLUSIONS: Reoperative cardiac surgery is associated with low operative morbidity and mortality at an experienced center. Early and late CPB strategies have comparable outcomes in the context of an image-guided, team-based strategy.

Adjunctive endovascular balloon fracture fenestration for chronic aortic dissection.

OBJECTIVE: Positive remodeling after thoracic endovascular aortic repair (TEVAR) for chronic thoracic aortic dissection is variable due to incomplete distal seal and retrograde false lumen perfusion. We assessed the outcomes of adjunctive balloon fracture fenestration (BFF) during TEVAR in patients with chronic aortic dissection complicated by negative remodeling. METHODS: From June 2013 to January 2016, 49 patients with chronic aortic dissection complicated by aneurysm due to negative remodeling underwent TEVAR with BFF. Contrast-enhanced computed tomography was performed before discharge, at 3 to 6 months, and annually. RESULTS: Intraoperatively, endovascular stent graft expansion was achieved in all patients. There was 1 hospital death due to visceral malperfusion related to acute-on-chronic dissection noted before planned BFF. There were no occurrences of paraplegia, 3 patients had stroke, and 3 had acute renal failure. Survival at 1 year was 91%. Late reintervention for incomplete false lumen exclusion was required in 16 patients and freedom from reintervention was 75% at 1 year. Thirty-six patients (73.5%) had complete false lumen thrombosis through the treated segment. True lumen area increased following TEVAR with BFF and continued to incrementally expand with subsequent aortic remodeling at 1-year follow-up. Thirteen patients had positive remodeling, defined as thrombosis of false lumen, ≥10% decrease in aortic dimension, and ≥10% increase in true lumen diameter. Patients with positive remodeling had an average decrease of 11 mm in maximal aortic diameter at final follow-up. CONCLUSIONS: BFF of chronic dissection membrane is a beneficial adjunct to TEVAR during short-term follow-up and may promote positive aortic remodeling and is worthy of further study.

Statin Therapy in Patients Undergoing Thoracic Aorta Replacement for Aortic Aneurysms.

BACKGROUND: Patients undergoing surgery for thoracic aortic aneurysms receive statin therapy out of proportion to cardiovascular comorbidity. We sought to determine the prevalence of statin use among patients presenting for thoracic aortic aneurysm surgery and investigate its effect on outcomes. METHODS: From January 1, 2005 to January 1, 2011, 1,839 consecutive patients underwent aortic replacement for degenerative thoracic aortic aneurysm at Cleveland Clinic. Of these, 771 (42%) were on statins preoperatively. Statin users (vs. nonstatin users) were older (65 ± 11 vs. 56 ± 16 years) and had more hypertension (78 vs. 59%). Propensity matching based on 56 preoperative variables other than lipid levels was used to compare outcomes among 570 matched patient pairs (74% of possible pairs). RESULTS: Propensity-matched statin and nonstatin users were aged 64 ± 11 years, 394 (69%) versus 387 (68%) were male, and 437 (77%) versus 442 (78%) had ascending aortic aneurysms, respectively. Overall, 25% of patients were followed for more than 8.2 years and 10% for more than 10 years. Perioperative outcomes were similar, including hospital mortality (11 [1.9%] vs. 5 [0.88%]) and stroke (22 [3.9%] vs. 13 [2.3%]), but 16 statin users (2.8%) versus 5 nonstatin users (0.88%) required temporary dialysis after surgery (p = 0.02). At 6 years, 3.7% of statin users versus 5.1% of nonstatin users (p[log-rank] = 0.5) underwent further aortic surgery, and at 10 years, mortality was 25% in both groups (p > 0.5). CONCLUSION: Patients presenting for thoracic aortic aneurysm surgery frequently receive unnecessary statins. Additionally, statin use was associated with more postoperative renal failure, but not less intermediate-term risk for aortic reintervention or all-cause mortality after surgery. Therefore, presence of a thoracic aortic aneurysm should not be considered an indication for statin therapy in the absence of well-established indications.

Evolution of Alternative-access Transcatheter Aortic Valve Replacement.

BACKGROUND: Transfemoral access is the most common approach for transcatheter aortic valve replacement (TAVR). However, a subset of patients require alternative access. This study describes the evolution and outcomes of alternative-access TAVR at Cleveland Clinic. METHODS: From January 2006 to January 2019, 2446 patients underwent TAVR, 414 (17%) through alternative access (247 transapical, 95 transaortic, 56 transaxillary, 2 transcarotid, 10 transiliac, 4 transcaval). Patients undergoing alternative-access TAVR had high preoperative risk. Propensity-matched comparisons were targeted at comparing transfemoral versus transaxillary approaches since 2012. RESULTS: Over time, the favored alternative-access approach shifted from transapical and transaortic to transaxillary. Pacemaker requirement was similar for alternative-access and transfemoral approaches. Compared with transfemoral access, major vascular injuries were higher in the alternative-access group (12 [2.9%] vs 27 [1.3%], P = .02), but minor vascular injuries were lower (13 [3.1%] vs 198 [9.8%], P < .0001). Non-risk-adjusted 5-year survival was lower in the alternative-access group (45% vs 59%). Compared with intrathoracic approaches (transapical and transaortic), transaxillary access was associated with fewer blood transfusions (12 [21%] vs 176 [51%], P < .0001), less prolonged ventilation (1 [1.8%] vs 38 [11%], P = .03), and shorter length of stay (median, 5 vs 7.5 days, P < .0001). Survival and major morbidity were similar in matched comparisons of the transfemoral and transaxillary approaches. No brachial plexus injuries occurred with transaxillary access. CONCLUSIONS: The transaxillary approach has emerged as our preferred alternative-access strategy for TAVR. It is associated with superior operative outcomes compared with transthoracic approaches, and results are comparable with those of the transfemoral approach.

Impact of Endovascular False Lumen Embolization on Thoracic Aortic Remodeling in Chronic Dissection.

BACKGROUND: Retrograde false lumen (FL) perfusion after thoracic endovascular aortic repair (TEVAR) for chronic dissection is a mode of treatment failure. Thrombosis of the FL is associated with favorable reverse remodeling. Objectives are to describe FL embolization (FLE) strategy and assess aortic remodeling and survival. METHODS: From January 2009 to December 2017, 51 patients with chronic dissection underwent FLE, most after previous TEVAR. Devices included a combination of iliac plug (29 patients), coils (19 patients), or nitinol plug (3 patients). Computed tomography was performed before discharge, at 3 months, and annually (median follow-up 2 years [range, 1 month to 7 years]). RESULTS: After FLE, mean maximum aortic diameter decreased (64.2 ± 12 mm to 61.0 ± 13 mm; P = .03), true lumen diameter increased (24.7 ± 10 mm to 33.7 ± 8 mm; P < .001), and FL diameter decreased (36.7 ± 12 mm to 25.6 ± 15 mm, P < .001). For reverse remodeling, FL thrombosis with ≥10% decrease in diameter and ≥10% increase in true lumen diameter was achieved in 20 (39.2%; 16 primarily, 4 secondarily). Nine patients progressed after the first FLE: persistent FL flow with increase in aortic diameter and underwent repeat FLE with complete thrombosis (n = 4) or open thoracoabdominal completion (n = 5). A total of 26 patients had indeterminate response (FL thrombosis without change in maximum diameter), and none have required reoperation. Six patients had complete obliteration of the entire FL. At last follow-up, 42 (82%) patients were alive. Three deaths were related to aortic pathology. CONCLUSIONS: FLE is an important endovascular adjunct to TEVAR promoting reverse aortic remodeling in select patients with chronic aortic dissection and persistent retrograde FL perfusion.

Serious Gastrointestinal Complications After Cardiac Surgery and Associated Mortality.

BACKGROUND: Severe gastrointestinal (GI) complications (GICs) after cardiac surgery are associated with poor outcomes. Herein, we characterize the severe forms of GICs and associated risk factors of mortality. METHODS: We retrospectively analyzed the clinically significant postoperative GICs after cardiac surgical procedures performed at our institution from January 2010 to April 2017. Multivariable analysis was used to identify predictors for in-hospital mortality. RESULTS: Of 29,909 cardiac surgical procedures, GICs occurred in 1037 patients (3.5% incidence), with overall in-hospital mortality of 14% compared with 1.6% in those without GICs. GICs were encountered in older patients with multiple comorbidities who underwent complex prolonged procedures. The most lethal GICs were mesenteric ischemia (n = 104), hepatopancreatobiliary (HPB) dysfunction (n = 139), and GI bleeding (n = 259), with mortality rates of 45%, 27%, and 17%, respectively. In the mesenteric ischemia subset, coronary artery disease (odds ratio [OR], 4.57; P = .002], coronary bypass grafting (OR, 6.50; P = .005), reoperation for bleeding/tamponade (OR, 12.07; P = .01), and vasopressin use (OR, 11.27; P < .001) were predictors of in-hospital mortality. In the HPB complications subset, hepatic complications occurred in 101 patients (73%), pancreatitis in 38 (27%), and biliary disease in 31 (22%). GI bleeding occurred in 20 patients (31%) with HPB dysfunction. In the GI bleeding subset, HPB disease (OR, 10.99; P < .001) and bivalirudin therapy (OR, 12.84; P = .01) were predictors for in-hospital mortality. CONCLUSIONS: Although relatively uncommon, severe forms of GICs are associated with high mortality. Early recognition and aggressive treatment are mandatory to improve outcomes.

Ruptured external jugular varix.

Venous dilations of the jugular veins are uncommon and external jugular varix even rarer. We present the case of a 57-year-old woman with ruptured external jugular varix and the surgical repair of such. Surgical intervention is warranted in these rare venous malformations to prevent known complications of thromboembolism and rupture.

Surgical Management of Carney Complex-Associated Pituitary Pathology.

BACKGROUND: Carney complex (CNC) is a familial neoplasia syndrome that is associated with pituitary-associated hypersecretion of growth hormone (GH) (acromegaly). The underlying cause of pituitary GH hypersecretion and its management have been incompletely defined. OBJECTIVE: To provide biological insight into CNC-associated pituitary pathology and improve management, we analyzed findings in CNC patients who underwent transsphenoidal surgery. METHODS: Consecutive CNC patients at the National Institutes of Health with acromegaly and imaging evidence of a pituitary adenoma(s) who underwent transsphenoidal resection of tumor(s) were included. Prospectively acquired magnetic resonance imaging and biochemical, surgical, and histological data were analyzed. RESULTS: Seven acromegalic CNC patients (2 male, 5 female) were included. The mean age at surgery was 29.7 years (range, 18-44 years). The mean follow-up was 4.7 years (range, 0.2-129 months). Magnetic resonance imaging revealed a single pituitary adenoma in 4 patients and multiple pituitary adenomas in 3 patients. Whereas patients with single discrete pituitary adenomas underwent selective adenomectomy, patients with multiple adenomas underwent selective adenomectomy of multiple tumors, as well as partial or total hypophysectomy. All adenomas were either GH and prolactin positive or exclusively prolactin positive. Pituitary tissue surrounding the adenomas in patients with multiple adenomas revealed hyperplastic GH- and prolactin-positive tissue. CONCLUSION: CNC-associated acromegaly results from variable pituitary pathology, including a single GH-secreting adenoma or multiple GH-secreting adenomas and/or GH hypersecretion of the pituitary gland surrounding multiple adenomas. Although selective adenomectomy is the preferred treatment for cases of GH-secreting adenomas, multiple adenomas with associated pituitary gland GH hypersecretion may require partial or complete hypophysectomy to achieve biochemical remission.

Impact of Cirrhosis in Patients Who Underwent Surgical Aortic Valve Replacement.

Cirrhosis is known to adversely affect cardiac surgery outcomes. Our objective was to quantify the morbidity, mortality, and cost that cirrhosis adds to surgical aortic valve replacement. From 1998 to 2011, 423,789 patients in the Nationwide Inpatient Sample Healthcare Cost Utilization Project underwent isolated aortic valve replacement; 2,769 (0.7%) had cirrhosis. Multivariable linear regression and 1:1 propensity matching were used to determine the effect of cirrhosis on postsurgical outcomes. The number of patients with cirrhosis who underwent surgical aortic valve replacement per year more than tripled during the 13-year study period. Patients with cirrhosis were more likely to be younger (p <0.0001), insured by Medicaid (p <0.0001), and operated on at an academic or high-volume hospital (p <0.05). Risk-adjusted mortality for patients with cirrhosis was 16%, compared with 5% for patients without cirrhosis. Risk factors for death included congestive heart failure, fluid and electrolyte imbalances, pulmonary circulation disorders, and weight loss. Among propensity-matched pairs, patients with cirrhosis had a higher mortality (odds ratio [OR] 3.6), risk of any complication [OR 1.5], and acute renal failure (OR 2.2). There was no increased risk of stroke, wound infection, blood transfusion, or pneumonia. The risk-adjusted length of stay (15 vs 12 days) and cost ($68,000 vs 56,000) were higher in patients with cirrhosis. In conclusion, the presence of cirrhosis poses a significant risk of death in patients who underwent surgical aortic valve replacement. When performed, the cost and length of stay are increased compared with those without cirrhosis.

Transmyocardial revascularization devices: technology update.

Transmyocardial laser revascularization (TMR) emerged as treatment modality for patients with diffuse coronary artery disease not amendable to percutaneous or surgical revascularization. The procedure entails the creation of laser channels within ischemic myocardium in an effort to better perfuse these areas. Currently, two laser devices are approved by the US Food and Drug Administration for TMR - holmium:yttrium-aluminum-garnet and CO2. The two devices differ in regard to energy outputs, wavelengths, ability to synchronize with the heart cycle, and laser-tissue interactions. These differences have led to studies showing different efficacies between the two laser devices. Over 50,000 procedures have been performed worldwide using TMR. Improvements in angina stages, quality of life, and perfusion of the myocardium have been demonstrated with TMR. Although several mechanisms for these improvements have been suggested, evidence points to new blood vessel formation, or angiogenesis, within the treated myocardium, as the major contributory factor. TMR has been used as sole therapy and in combination with coronary artery bypass grafting. Clinical studies have demonstrated that TMR is both safe and effective in angina relief long term. The objective of this review is to present the two approved laser devices and evidence for the safety and efficacy of TMR, along with future directions with this technology.

Transapical sutureless aortic valve implantation under magnetic resonance imaging guidance: Acute and short-term results.

OBJECTIVES: Despite the increasing success and applicability of transcatheter aortic valve replacement, 2 critical issues remain: the durability of the valves, and the ideal imaging to aid implantation. This study was designed to investigate the transapical implantation of a device of known durability using real-time magnetic resonance imaging (MRI) guidance. METHODS: A sutureless aortic valve was used that employs a self-expanding nitinol stent and is amenable to transapical delivery. MRI (1.5-T) was used to identify the anatomic landmarks in 60-kg Yucatan swine. Prostheses were loaded into an MRI-compatible delivery device with an active guidewire to enhance visualization. A series of acute feasibility experiments were conducted (n = 10). Additional animals (n = 6) were allowed to survive and had follow-up MRI scans and echocardiography at 90 days postoperatively. Postmortem gross examination was performed. RESULTS: The valve was MRI compatible and created no significant MRI artifacts. The 3 commissural struts were visible on short-axis view; therefore, coronary ostia obstruction was easily avoided. The average implantation time was 65 seconds. Final results demonstrated stability of the implants with preservation of myocardial perfusion and function over 90 days: the ejection fraction was 48% ± 15%; the peak gradient was 17.3 ± 11.3 mm Hg; the mean gradient was 9.8 ± 7.2 mm Hg. Mild aortic regurgitation was seen in 4 cases, trace in 1 case, and a severe central jet in 1 case. Prosthesis positioning was evaluated during gross examination. CONCLUSIONS: We demonstrated that a sutureless aortic valve can be safely and expeditiously implanted through a transapical approach under real-time MRI guidance. Postimplantation results showed a well-functioning prosthesis, with minimal regurgitation, and stability over time.

Real-time magnetic resonance-guided aortic valve replacement using Engager valve.

PURPOSE: New-generation stented bioprostheses coupled with better imaging modalities are expanding the clinical utility of transcatheter aortic valve replacement (TAVR). This study aimed at evaluating the feasibility of real-time cardiovascular magnetic resonance (rtCMR) -guided TAVR using the Medtronic Engager aortic valve system in a preclinical model. DESCRIPTION: The Engager delivery device was slightly modified to make it CMR-compatible. Ten Yucatan swine underwent rtCMR-guided transapical TAVR. Postplacement phase-contrast and first-pass perfusion CMR sequences were used to evaluate for aortic regurgitation and myocardial perfusion, respectively. EVALUATION: Real-time CMR provided excellent visualization of cardiac anatomy during TAVR. Nine of 10 animals had proper valve placement in the aortic annulus as determined by CMR and confirmed by necropsy inspection. Postplacement phase-contrast scans confirmed no intravalvular or paravalvular leaks. Perfusion scans demonstrated sufficient coronary flow. Roentgenographs confirmed proper placement of the prostheses. CONCLUSIONS: The Engager valve can be implanted transapically under rtCMR guidance with a modified, CMR-compatible delivery device in a preclinical model. Cardiovascular magnetic resonance allowed for accurate preplacement evaluation, real-time guidance, and postplacement functional assessment.