Efficacy of regional saturation of oxygen monitor using near-infrared spectroscopy for lower limb ischemia during minimally invasive cardiac surgery

Cannula to Femoral Artery Diameter Ratio Predicts Potential Lower-Limb Ischemia in Minimally Invasive Cardiac Surgery With Femoral Cannulation

OBJECTIVE

Lower-limb ischemia is a complication of minimally invasive cardiac surgery with femoral cannulation. Herein, we verified our strategy using distal perfusion cannulation (DPC) against this complication.

METHODS

We retrospectively assessed 91 cases of aortic valve replacement with femoral cannulation between January 2019 and March 2023. DPC was applied when lower-limb tissue oxygenation index declined by ≥20%. The cannula to femoral artery diameter ratio (C/FA) was calculated by dividing the cannula size (Fr) divided by 3 by the femoral artery inner diameter (mm). Postoperative maximum creatinine kinase (CKmax), lactate dehydrogenase (LDHmax), and lactate levels were analyzed, and univariable logistic regression and receiver operating characteristic curve analyses were employed to determine DPC predictors and the cutoff C/FA for DPC, respectively. Patients without DPC were divided into 2 subgroups based on the cutoff C/FA for further comparisons.

RESULTS

DPC was required in 9 patients. Symptomatic ischemia was not observed. All laboratory data were similar in the DPC and non-DPC groups. C/FA was significantly associated with DPC (odds ratio = 1.27, 95% confidence interval: 1.09 to 1.47, P = 0.002), and the cutoff C/FA was 0.70 (sensitivity = 0.89, specificity = 0.80). In the non-DPC group, CKmax (P = 0.027) and LDHmax (P = 0.041) were significantly higher in patients with C/FA ≥0.7 (n = 16) than in those with C/FA <0.7 (n = 66).

CONCLUSIONS

Our strategy for preventing symptomatic ischemia is reasonable and could be almost achieved without DPC when C/FA is <0.7. C/FA also predicts asymptomatic potential ischemia, and proactive DPC is preferable when C/FA is ≥0.7.

Short- and Midterm outcomes of modified robotic tricuspid annuloplasty for secondary tricuspid regurgitation

BACKGROUND

Despite the growing popularity of robotically assisted mitral repair, robotically assisted tricuspid repair has not been widely adopted. We assessed the safety and feasibility of robotic tricuspid annuloplasty with continuous sutures for tricuspid regurgitation (TR).

METHODS AND RESULTS

We studied consecutive 68 patients (median age, 74 years) with secondary TR who underwent tricuspid annuloplasty using continuous sutures with (n = 61) and without mitral valve repair (n = 7) from 2018 to 2021. Robotic tricuspid annuloplasty consists of continuous sutures with flexible prosthetic band to the tricuspid annulus using two V-Loc barbed sutures (Medtronic Inc., Minneapolis, MN). Concomitant maze procedure was performed in 45 (66%) patients. Robotic tricuspid annuloplasty with continuous sutures was successfully performed. There was no in-hospital or 30-day mortality; 65 patients (96%) did not experience major surgery-related complications. Preoperatively, the TR grade was mild in 20 (29%) patients and mildly higher in 48 (71%). Postoperatively, the TR severity significantly improved, with TR grade mildly higher in 9% at hospital discharge and 7% at 1-year follow-up (p < 0.001). The 1-year and 2-year freedom rates from heart failure were 98% and 95%, respectively.

CONCLUSIONS

Robotic tricuspid annuloplasty with continuous sutures is safe and feasible alone or concomitant with mitral valve repair. It offered sustained improvement in TR severity and might prevent heart failure readmission.

Incidence, predictors and vascular sequelae of distal limb ischemia in minimally invasive cardiac surgery with femoral artery cannulation: an observational cohort study

Literature regarding monitoring and consequences of distal limb ischemia due to femoral artery cannulation for Minimally Invasive Cardiac Surgery (MICS) remains limited. The primary objective was to determine its incidence, defined as a ≥ 15% difference in regional Oxygen Saturation (rSO₂) lasting ≥ four consecutive minutes between the cannulated and non-cannulated limb. The secondary objectives included: determination of distal limb ischemia, defined as a Tissue Oxygenation Index (TOI) < 50% in the cannulated limb, identification of predictors for distal limb ischemia, determination of a possible association of NIRS-diagnosed ischemia with acute kidney injury, and the need for vascular surgery up to six months after cardiac surgery. A prospective, observational cohort study with blinded rSO₂-measurements to prevent intraoperative clinical decision-making. A single-center, community-hospital, clinical study. All consecutive patients ≥ 18 years old, and scheduled for predefined MICS. Patients underwent MICS with bilateral calf muscle rSO₂-measurements conducted by Near-Infrared Spectroscopy (NIRS). In total 75/280 patients (26.79%) experienced distal limb ischemia according to the primary objective, while 18/280 patients (6.42%) experienced distal limb ischemia according to the secondary objective. Multivariate logistic regression showed younger age to be an independent predictor for distal limb ischemia (p = 0.003). None of the patients who suffered intraoperative ischemia required vascular surgery within the follow-up period. The incidence of NIRS-diagnosed ischemia varied from 6.4% to 26.8% depending on the used criteria. Short and long-term vascular sequelae, however, are limited and not intraoperative ischemia related. The added value of intraoperative distal limb NIRS monitoring for vascular reasons seems limited. Future research on femoral artery cannulation in MICS should shift focus to other outcome parameters such as acute kidney injury, postoperative pain or paresthesias.

Does a Small Body Have a Negative Impact on Minimally Invasive Mitral Valve Surgery?

Backgrounds

Minimally invasive mitral valve surgery (MIMVS) in patients with a small body presents surgeons with a technically difficult surgical maneuver. We hypothesized that physique might negatively influence the safety and technical complexity of MIMVS.

Methods

One hundred and twenty-one patients underwent MIMVS in our institution between May 2014 and April 2020. These patients were categorized into two groups. The first group was the small physique group (n = 20) consisting of patients with a stature &lt;150 cm. The second group was the normal physique group (n = 101) consisting of patients with a stature &gt;150 cm. The primary endpoint was freedom from death and major adverse cardiovascular and cerebrovascular events (MACCE). The secondary endpoint was freedom from moderate or severe mitral regurgitation.

Results

Cardiopulmonary bypass time (130 ± 29 vs. 156 ± 55 min, p = 0.02) and aortic cross-clamp time (75 ± 27 vs. 95 ± 39 min, p = 0.03) were significantly shorter in the small physique group. Both in the early and midterm periods, there was no significant difference in the mortality (early, 5.0 vs. 1.0%, p = 0.30. midterm, 5.0 vs. 1.0%, p = 0.09), MACCE (early, 5.0 vs. 6.9%, p = 0.65. midterm, 5.0 vs. 5.9%, p = 0.93) and the residual MR (early, 0 vs. 1.0%, p = 0.66. midterm, 5.0 vs. 4.9%, p = 0.93) between the two groups.

Conclusions

Small physique is not a hurdle for MIMVS in terms of the safety of the operation.

Benefits of robotically-assisted surgery for complex mitral valve repair

OBJECTIVES

To determine whether robotic mitral valve repair can be applied to more complex lesions compared with minimally invasive direct mitral valve repair through a right thoracotomy.

METHODS

We enrolled 335 patients over a 9-year period; 95% of the robotic surgeries were performed after experience performing direct mitral valve repair.

RESULTS

The mean age in the robotic versus thoracotomy repair groups was 61 ± 14 vs 55 ± 11 years, respectively (P < 0.001); 97% vs 100% of the patients, respectively, had degenerative aetiologies. Repair complexity was simple in 106 (63%) vs 140 (84%), complex in 34 (20%) vs 20 (12%) and most complex in 29 (17%) vs 6 (4%) patients undergoing robotic versus thoracotomy repair, respectively. The average complexity score with robotic repair was significantly higher versus thoracotomy repair (P < 0.001). The robotic group underwent more chordal replacement using polytetrafluoroethylene and less resections. All patients underwent ring annuloplasty. Cross-clamp time did not differ between the groups, and no strokes or deaths occurred. More patients undergoing robotic repair underwent concomitant procedures versus the thoracotomy group (30% vs 14%, respectively; P < 0.001). The overall repair rate was 100%, with no early mortality or strokes in either group. Postoperative mean residual mitral regurgitation was 0.3 in both groups, and the mean pressure gradient through the mitral valve was 2.4 vs 2.7 mmHg (robotic versus thoracotomy repair, respectively; P = 0.031).

CONCLUSIONS

Robotic surgery can be applied to repair more complex mitral lesions, with excellent early outcomes.

Utility of Ultrasonographic Assessment of Distal Femoral Arterial Flow during Minimally Invasive Valve Surgery

PURPOSE

To evaluate the utility of ultrasonographic assessment of blood flow to the lower limb below the cannulation site in minimally invasive cardiac surgery (MICS).

METHODS

Twenty-two patients who underwent ultrasonographic assessment in MICS were reviewed retrospectively. In all patients, the right femoral artery was used for arterial cannulation. Ultrasonographic assessment was performed using a 15-MHz ultrasonography small probe, and regional oxygen saturation was monitored by near-infrared spectroscopy (NIRS).

RESULTS

The mean flow velocity at the distal side of the cannulation site was 46.2 ± 25.4 cm/s. In six patients, a >40% decreased from baseline regional oxygen saturation was observed. In five of the six patients, the flow velocity was very slow, and spontaneous echo contrast was also observed in three cases. Their regional oxygen saturation was improved rapidly after distal leg perfusion. In the remaining case, the flow velocity was not decreased. In another one case, the stenosis at the cannulation site was detected after decannulation and repaired immediately. No limb ischemic complications were observed in this series.

CONCLUSION

Ultrasonographic assessment combined with the NIRS monitoring is useful to prevent lower limb ischemic complications after femoral arterial cannulation in MICS.

Regional oxygen saturation change rate for detection of leg ischemia in minimally invasive cardiac surgery

INTRODUCTION

The criteria for placement of distal perfusion cannulas vary among reports. This cohort study aimed to establish a reproducible method to monitor critical leg ischemia during minimally invasive cardiac surgery.

METHODS

We included 121 patients who underwent minimally invasive cardiac surgery via right thoracotomy with right femoral arterial cannulation from 2015 to 2018. The change rate of regional oxygen saturation (ΔrSO₂) was calculated as follows: rSO₂ (baseline) - rSO₂ (actual number)/rSO₂ (baseline). Patients were divided into Group N (ΔrSO₂ < 40%): 100/121 (83%) and Group H (ΔrSO₂ > 40%, <10 minutes if >40%): 21/121 (17%). A distal perfusion cannula was placed when ΔrSO₂ was >40% over 10 minutes.

RESULTS

No patients experienced significant leg ischemia. Significantly longer cardiopulmonary bypass and aortic cross-clamp times were observed in Group H than in Group N (cardiopulmonary bypass time, 129 ± 36 minutes (Group N) vs. 151 ± 34 minutes (Group H), p = 0.01). ΔrSO₂ correlated positively with plasma creatine phosphokinase elevation (R = 0.40, p < 0.001) on postoperative day 1. Serum lactate on intensive care unit admission showed a significant positive correlation (R = 0.40, p < 0.001) with ΔrSO₂.

CONCLUSION

ΔrSO₂ measurement by near-infrared spectroscopy can facilitate distal leg perfusion monitoring and assist surgeons in preventing critical leg ischemia during minimally invasive cardiac surgery.

Femoral artery anatomy is a risk factor for limb ischemia in minimally invasive cardiac surgery

OBJECTIVE

In minimally invasive cardiac surgery (MICS), femoral artery cannulation during cardiopulmonary bypass (CPB) can cause limb ischemia. This study evaluated the association between femoral artery anatomy and the risk of limb ischemia in MICS.

METHODS

Eighty-one patients who underwent MICS with CPB using single femoral artery cannulation between 2010 and 2018 were included. The patients were stratified by their femoral artery diameter and anatomy of ectopic side branch, i.e., medial or lateral femoral circumflex arteries: Type A, deep femoral artery (DFA) ≥ superficial femoral artery (SFA); type B, DFA < SFA with an ectopic side branch of the common femoral artery (CFA); type C, DFA < SFA with an ectopic side branch at the CFA bifurcation; and type D, DFA < SFA without an ectopic side branch. The ratio of the postoperative creatine kinase concentration and the cross-sectional area of the femoral muscles (CK/MA) was used as a surrogate marker of limb ischemia. Predictors of high CK/MA were evaluated.

RESULTS

No critical limb ischemia was observed in this study. The median postoperative creatine kinase and CK/MA were 1954 (1305-2872) IU/l and 15.2 (9.2-19.8) IU/l/cm². Multivariable logistic regression found that anatomical type D (odds ratio 4.19, 95% confidence interval: (1.26-14.0); p = 0.020) and prolonged CPB time (OR 1.01, 95% CI (1.00-1.02); p = 0.045) were independent risk factors of high CK/MA.

CONCLUSION

Anatomical type D and prolonged CPB time were associated with risk of limb ischemia in MICS.