Calf Muscle Oxygen Saturation during 6-Minute Walk Test and Its Relationship with Walking Impairment in Symptomatic Peripheral Artery Disease

BACKGROUND

Impaired microcirculation is associated with poor walking capacity in symptomatic peripheral artery disease (PAD) patients during treadmill test; however, this test does not simulate the efforts of daily walking of these patients. Thus, the aim of the study was to describe the microcirculation responses during a 6-minute walk test (6MWT) and to analyze the relationship between microcirculation indicators and walking impairment in symptomatic PAD patients.

METHODS

Thirty-four patients were included (mean age = 67.6 ± 11.2 years). Their clinical characteristics were collected, and they performed a 6MWT, in which the initial claudication distance (ICD) and total walking distance (TWD) were recorded. During and after the 6MWT, calf muscle oxygen saturation (StO₂) parameters were monitored continuously to measure microcirculation behavior. The association between calf muscle StO₂ parameters and walking impairment were analyzed by Pearson or Spearman correlations.

RESULTS

Walking impairment was not associated with any StO₂ parameters during exercise. In contrast, after 6MWT, recovery time of StO₂ (r = -0.472, P = 0.008) and recovery time to maximal StO₂ (r = -0.402, P = 0.019) were negatively correlated with ICD. Furthermore, the distance walked under claudication symptoms (ΔTWD-ICD) was positively correlated with recovery time to maximal StO₂ (r = 0.347, P = 0.048).

CONCLUSIONS

In symptomatic PAD patients, shorter ICD values during a 6MWT are associated with a delayed recovery in calf muscle StO₂ after exercise. Calf muscle StO₂ parameters decrease subtly during 6MWT, suggesting that the degree of ischemia in the calf muscle during ground walking, simulating efforts of the daily walking, is relatively low.

Infection related to implantable central venous access devices in cancer patients: epidemiology and risk factors

OBJECTIVE

To describe the epidemiology of infections related to the use of implantable central venous access devices (CVADs) in cancer patients and to evaluate measures aimed at reducing the rates of such infections.

DESIGN

Prospective cohort study.

SETTING

Referral hospital for cancer in São Paulo, Brazil.

PATIENTS

We prospectively evaluated all implantable CVADs employed between January 2009 and December 2011. Inpatients and outpatients were followed until catheter removal, transfer to another facility, or death.

METHODS

Outcome measures were bloodstream infection and pocket infection. We also evaluated the effects that the creation of a multidisciplinary team for CVAD care, avoiding in-hospital implantation of CVADs, and limiting CVAD insertion in neutropenic patients have on the rates of such infections.

RESULTS

During the study period, 966 CVADs (mostly venous ports) were implanted in 933 patients, for a combined total of 243,792 catheter-days. We identified 184 episodes of infection: 154 (84%) were bloodstream infections, 21 (11%) were pocket infections, and 9 (5%) were surgical site infections. During the study period, the rate of CVAD-related infection dropped from 2.2 to 0.24 per 1,000 catheter-days ([Formula: see text]). Multivariate analysis revealed that relevant risk factors for such infection include surgical reintervention, implantation in a neutropenic patient, in-hospital implantation, use of a cuffed catheter, and nonchemotherapy indication for catheter use.

CONCLUSIONS

Establishing a multidisciplinary team specifically focused on CVAD care, together with systematic reporting of infections, appears to reduce the rates of infection related to the use of these devices.

Totally implantable femoral vein catheters in cancer patients

INTRODUCTION

Totally implantable devices are increasingly being utilized for chemotherapy treatment of oncological patients. When it is impossible to implant the reservoir on the anterior wall of the thorax, or when there is an obstruction of the superior vena cava system, alternative access routes must be sought. Of these, the femoral vein is the most utilized. Few studies have been performed to analyse the results obtained from the implantation and utilization of such catheters in the femoral vein. The goal of this work was to prospectively study the results obtained from the implantation of 20 TIC in femoral veins in a large-sized cancer hospital with its own dedicated vascular clinical team.

MATERIAL AND METHODS

Twenty femoral TIC were inserted in 20 patients out of a group of 560 cancer patients submitted to TIC implantation for chemotherapy. Evaluations were made of the early and late-stage complications and patient evolution until removal of the device, death or the end of the treatment.

RESULTS

The prospective analysis showed a mean duration of 215 days for the catheters. There were 16 patients with no complications. There were no early complications. Among the late complications, three were infections, representing 0.69/1000 days of catheter use, and one was a deep vein thrombosis (0.23/1000 days of catheter use). One catheter was removed due to primary bacteremia and one due to subcutaneous pocket infection. Fourteen patients died while the catheter was functioning and four patients are still making use of the catheter.

CONCLUSION

The low rate of complications implying catheter loss in this study confirms the safety and convenience of the use of femoral TIC in patients who cannot be submitted to implantation in the superior vena cava system.