ORIGINAL ARTICLE Year : 2021  |  Volume : 10  |  Issue : 3  |  Page : 216-221

A new functional indoor ramp walk test among stable perioperative valve replacement patients – An observational crossover study

Manivel Arumugam1, Mahesh Ramaraj2, Baskaran Chandrasekaran3, Murugesan Periyanarkunam Ramaiya4, Pitchaimani Govindharaj5
1 Department of Pulmonary Medicine, Pulmonary Rehabilitation Unit, PSG Institute of Medical Sciences and Research, PSG Hospitals, Coimbatore, Tamil Nadu, India
2 PSG College of Physiotherapy, Coimbatore, Tamil Nadu, India
3 Department of Exercise and Sports Sciences, School of Allied Health Sciences, Manipal University, Manipal, Karnataka, India
4 Department of Cardiothoracic Surgery, PSG Institute of Medical Sciences and Research, PSG Hospitals, Coimbatore, Tamil Nadu, India
5 Department of Allied Health Sciences, Sri Ramachandra Institute of Higher Education and Research (DU), Chennai, Tamil Nadu, India

Date of Submission13-May-2020Date of Acceptance21-Mar-2021Date of Web Publication04-Aug-2021

Correspondence Address:
Dr. Manivel Arumugam
Senior Physiotherapist, Department of Pulmonary Medicine, Pulmonary Rehabilitation Unit, PSG Institute of Medical Sciences and Research, PSG Hospitals, Coimbatore, Tamil Nadu
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/ijhas.IJHAS_113_20

BACKGROUND : Postcardiac valve replacement patients face difficulty in their day-to-day functional activities, especially during climbing stairs and walking uphill or on a ramp in society. Assessing the uphill walking capacity, there is a dearth of functional stress test over routinely used six-min walk test (6MWT). Therefore, a new three-min steep ramp walk test (3MRWT) was constructed to meet the demands similar to an uphill walk and may provide more functional stress than routinely used 6MWT.
MATERIALS AND METHODS: Observational crossover study was conducted with 30 stable postoperative either mitral or aortic or double valve replacement patients, who were as inpatients in the Department of Cardiothoracic and Vascular Surgery, Multispecialty Medical College Hospital, Coimbatore, India. The participants were assigned to walk 3MRWT and 6MWT simultaneously on the 5th postoperative day.
RESULTS: The results revealed that the mean distance covered in 6MRWT was 273.4 ± 45.06 m, and in 3MWT, it was 149.7 ± 37.8 m. A highly positive correlation was observed between 3MRWT and 6MWT distance covered by the patients with valve replacement (r = 0.834).
CONCLUSION: The study shows that 3MRWT is valid over routinely available 6MWT and may provide higher functional stress in a shorter duration than later in valvular replacement patients in assessing the maximal functional capacity during discharge.

Keywords: Exercise test, functional capacity, six-min walk test, three-min ramp walk test, valve replacement

How to cite this article:
Arumugam M, Ramaraj M, Chandrasekaran B, Ramaiya MP, Govindharaj P. A new functional indoor ramp walk test among stable perioperative valve replacement patients – An observational crossover study. Int J Health Allied Sci 2021;10:216-21
How to cite this URL:
Arumugam M, Ramaraj M, Chandrasekaran B, Ramaiya MP, Govindharaj P. A new functional indoor ramp walk test among stable perioperative valve replacement patients – An observational crossover study. Int J Health Allied Sci [serial online] 2021 [cited 2021 Aug 6];10:216-21. Available from: https://www.ijhas.in/text.asp?2021/10/3/216/322985   Introduction 

Perioperative functional capacity determines the early community integration and quality of life (QoL) in patients who have undergone surgeries.[1] Hence, functional capacity becomes an integral component of the perioperative evaluation after cardiothoracic surgery.[2] Preoperative activity level, duration of intensive care, and quality perioperative care determine the functional capacity of perioperative period in postoperative cardiac patients.[2] The patients who have undergone heart valve replacement surgeries struggle with their functional activities, especially during climbing stairs and walking uphill or on a steep ramp.[3] The evaluation and measurement of QoL is essential in the process of clinical decision-making, determination of therapeutic benefits and the perception, the perioperative client has about his/her illness.[4]

The most popular clinical exercise tests in order of increasing complexity are six-min walk test (6MWT),[5] step test,[6] shuttle walk test,[7] arm-crank ergometry test,[8] and cardiac stress test.[9],[10] The widespread acceptance of walk tests relates to their convenience, low cost, and presumed ease of completion. However, none of these tests have differences in assessing cardiac ability, ease, and cost. Few may not be applicable for the immediate perioperative functional capacity screening, especially treadmill or cycle-based exercise testing.[11]

The 6MWT is a common outcome measurement for evaluating the functional capacity, the effects of intervention and prognostic significance in early cardiac surgeries and coronary heart diseases,[5],[12],[13] valvular heart,[14],[15] heart failure,[16],[17],[18] and chronic respiratory conditions.[19],[20] 6MWT can be easily administered in elderly and severely debilitated individuals who are unable to perform symptom-limited exercise tests (bicycle/treadmill).[21],[22] Recently, inability to climb two flights of stairs is related to poor prognosis of perioperative valvular surgical patients.[23] There is a dearth of literature to test the functional ability to walk uphill for perioperative valvular patients.

To assess a higher functional ability (uphill or ramp walking) of stable perioperative cardiac valvular patients, we need a short-term functional stress test to stress over the routinely administered 6MWT. We developed and tested a three-min Ramp Walk Test (3MRWT- three-min Ramp Walk Test),[24] which might fulfill the criteria of an uphill or ramp functional walk test for perioperative cardiac valvular patients. Although ramp walking can be trained using the treadmill, it may not be feasible for the Indian patients due to lack of familiarity, cost, and user-friendly. Further transfer effect of treadmill walk to real time is at stake.

When developing a new functional walk test, we should consider two facts: it should produce a similar and significant cardiopulmonary response when compared with routinely administered 6MWT, and these tests should be reliable, valid, and identical to the criterion walk test. Hence, the purpose of the study is to compare 3MRWT with 6MWT in patients with heart valve replacement to demonstrate the significance of 3MRWT over 6MWT as a functional stress test. We hypothesized that 3MRWT would produce a similar or higher cardiovascular stress in a significantly lesser time frame in perioperative valvular surgical patients compared to 6MWT.

  Methods 

The study was conducted with 30 patients with a mean age of 44 ± 13.54 years who were recruited. Among them, 15 were undergone mitral valve replacement, 8 were atrial valve replacement, and 7 were double-valve replacement (DVR).

Study setting

The observational crossover study was conducted from October 2013 to April 2015 in the Department of Cardiothoracic and Vascular Surgery, Multispecialty Medical College Hospital, Coimbatore, state of Tamil Nadu, India.

Ethical consideration

This study was approved by the Ethical Committee, PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India. In addition, voluntary written consent was obtained from the participants.

Participants eligibility

Inclusion

Stable postoperative patients with valve replaced of mitral, aortic, and or both were included in the study. The stability was directed by the cardiothoracic surgeon involved in the study based on the hemodynamic stability and the absence of postoperative complications on the 5th postoperative day (POD). Both males and females (18–65 years of age) with the criteria of completing 5th postoperative day, prothrombin time and international normalized ratio (PT INR) <3, ejection fraction >40%, and able to follow-up commands in English and regional language (Tamil) were included in the study.

Exclusion

Accordingly, the American Association of Respiratory Care on contraindications for 6MWT[25],[26] was followed to exclude the patient. The participants who were hemodynamically unstable (systolic blood pressure [SBP] >180, diastolic blood pressure [DBP] >100, heart rate [HR] >90% Maximum Heart Rate (MHR), resting oxygen saturation [SpO2] <88%, postoperative pulmonary complication [X-ray shadows, oxygenation index impaired, and pyretic > 100°F) were excluded from the study. Patients with uncompensated pleural effusion, pneumothorax, uncompensated life-threatening arrhythmias, ST changes >2 mm up or downsloping, PT INR >3, and ejection fraction <40% were also excluded. Patients who were on continuous sedatives, anesthetics and analgesics infusion pumps, severe uncompensated postoperative pericardial effusions, tamponade, arrests intraoperative, and musculoskeletal disorders limiting their walkability were also excluded from the study.

Sample size and sampling technique

Sample size

To determine the sample size, minimal correlation should be of 40 % (r=0.4) between 6 MWT and 3 MRWT. In addition, the smallest difference should be of 70% between two tests. Walking distance and vital sign responses ought to be at level of 95% significance (P < 0.05). The power of study must be 90%.[17] The required sample size was at least 45 patients. On account of time limitation and criteria of the study, only 39 patients were able to be screened. Out of 39 patients, only 30 of them were eligible for the study according to the inclusion criteria [Figure 1].

Sampling technique

This study was conducted with 30 patients selected by the purposive consecutive sampling method. Followed by, the patients were randomized using lottery method for the sequence of the either 6MWT or 3MRWT.

Primary outcome measures

Six-min walk distance

The test was conducted as per the American Thoracic Society guidelines.[26] Patients were instructed to walk in the corridor which is 30 m distance demarcated by the cones at the starting and the end of the walkway. The maximum distance covered in the s6 min is measured by the sum of number of laps completed and the partial distance covered in the last lap. The encouragement at the end of every minute is standardized by the tape recorder to avoid feedback bias on the walk distance covered by the patients.[26]

Three-min ramp walk distance

Twenty-meter ramp is commonly available in the hospital wards with an elevation angle of 30°; elevation is measured with 10 feet length and 1-foot steep raise (10ft: 1ft) as per standardization of hospital ramps globally.[27],[28] The ramp setup is feasible and inevitable in the hospital engineering setup with standardization of 57 feet elevation, 4 feet of flat surface.[24],[29] We have published the feasibility and applicability of a 20-m ramp in healthy volunteers earlier.[24]

Secondary outcome measures

The heart rate and pulse SpO2 were measured throughout the 6MWT and 3MRWT using a pulse oximeter (Philips Respironics, United States). Further exertion was measured through Modified Borg Rate of Perceived Exertion Scale (0–10 Likert scale) and fatigue was measured through visual analog scale, a Likert scale of 0–10. Both exertion and fatigue were quantified by the self-report of the patients after each walk test.

Procedure

The patients were screened by surgeon or the cardiac physician in the 5th POD and assessed for field walk test. The test was done on the 5th POD and this would be the ideal day for mobilization around corridors according to hospital policy. The test was performed by the first author after obtaining the written informed consent and having performed the screening. Before examining the walk test, the baseline measurement of the participating patients was measured and assigned randomly for either 6MWT or 3MRWT as the first test. Accordingly, randomizations of the next test either 6MWT or 3MRWT were administered, after 6 h of washout time. The data were collected before, during, and immediately after each test, which is includes; distance walked measured in meter, and finger pulse oximeter was used to measure the pulse rate and SpO2. In addition, dyspnea, leg fatigue, and blood pressure (BP) were also recorded. After the test, the patients were adequately assessed for adverse events and allowed to leave the testing area when their BP and pulse rate returned to pretest or baseline levels.

Data analysis

The results were presented in the form of mean and standard deviation (SD). The continuous variables of distance walked and other hemodynamic variables were tested for normality through Shapiro–Wilk Test. Paired t-test was used to find out any significant difference between baseline and post walk test (6MWT and 3MRWT). The relationship between the results of 3MRWT and 6MWT was calculated by Pearson's and Spearman rank correlation coefficient (r). P < 0.05 was considered significant. All these statistical treatments were performed through SPSS 17.0 (IBM SPSS, 2007, Chicago, IL, USA).

  Results 

This study included 30 patients who completed the study. Of the 30 patients, 17 were male and 13 were female. All patients found it easy to pace themselves and no difficulties were encountered in administering both the tests. The profile of the patients is shown in [Table 1]. The distance covered in 6MWT was 273.4 ± 45.06 m, and in 3MRWT, it was 149.7 ± 37.8 m at a significant difference of P < 0.001.

[Table 2] summarizes the changes in cardiorespiratory parameters during the 3MRWT and 6MWT. It shows the mean ± SD values of SpO2, HR, SBP and DBP, shortness of breath, and fatigue at the beginning and the end of each exercise test. The baseline values and end of the test values of SpO2, HR, SBP and DBP, shortness of breath, and fatigue in both 6MWT and 3MRWT showed significance at P < 0.05. At the end of this study ( 6 MWT and 3 MRWT), results showed a moderate to high correlation in the test values such as SPO2, HR, SBP, DBP, shortness of breath, and leg fatigue between 6 MWT and 3 MRWT.

Table 2: Changes in cardiorespiratory parameters during 3-min ramp walk test and 6-min walk test

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Among the study patients, there was no statistically significant difference between the male and female patients in distance covered both the 6MWT (male – 274 ± 44 and female – 145 ± 35; P > 0.05) [Figure 2] and 3MWT (male – 274 ± 44 and female – 273 ± 48; P > 0.05) [Figure 3]. A moderate-to-high correlation was observed between distances covered by the patients with valve replacement in both 3MRWT and 6MWT (r = 0.834 at P < 0.01) and it is shown in [Figure 4]. The relation between walk distance and age, height, and weight is found to be 0.43, 0.48, and 0.64, respectively, at a significant level P < 0.05. The mean difference between the hemodynamic parameters is highly significant at P < 0.001 among both the tests.

Figure 4: Correlation between three-min ramp walk test and 6-min walk test

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  Discussion 

With our counterbalanced crossover study, we demonstrated that 3MRWT is valid in assessing functional capacity in uphill walking similar to routine 6MWT. The findings of this study are consistent with the findings of the study conducted by Someya et al., who established a relation among stroke volume, cardiac index, and the distance walked and revealed that there is a significant correlation exists with the cardiac hemodynamic stress and the distance walked in the functional walk tests.[30] A recent study by Chen et al. has demonstrated a significant reliability of 6MWT and its ability to determine the QoL in perioperative cardiac surgery. However, the 6MWT estimates walking ability in level ground only.[31] In day-to-day activities, people walking activities involve a lot more than level walking and not limiting to ramp climbing such as malls, hospitals, exhibition, and showrooms. Hence, we demonstrated 3MRWT to estimate appropriately the walking ability in uphill.

The 6MWT was significant with the peak oxygen consumption (VO2 Peak). Though this study was not employed with arterial blood gas analysis, we can confer that the values such as SPO2, HR, BP, and RR are closely related with peak oxygen consumption and determinants of the same. As the cardiopulmonary system should work in harmony to improve VO2 Peak, the increase in hemodynamic responses may indirectly increase the VO2 Peak. As the ground inclination increases, higher muscular contraction needs a greater circulation and ventilation inducing a ventilation perfusion demand which, in turn, increases the hemodynamic stress than the level walking (6MWT).

We found an excellent correlation observed between 3MWRT and 6MWT. Earlier cross-sectional trial found a significant relation between shuttle walk and other hemodynamic parameters (distance: R = 0.98; HR: R = 0.96; exertion: R = 0.89) but not 6MWT. This study also agrees the moderate-to-excellent relation among the 3MRWT and other hemodynamic parameters.[32] To our knowledge, this is the first study to demonstrate a new functional ramp test in a hospital setting for assessing perioperative evaluation of valve replacement patients. The 3MRWT could be used for preoperative, postoperative evaluations and for measuring the response to therapeutic interventions in patients with cardiac and pulmonary diseases.

The limitations of this study were it was conducted with a small sample size and the participants included too were not homogeneous (mitral, aortic, and DVR). Besides, these results can be generalized only to the perioperative patients undergone ramp walk test in the ramp with specified parameters. Further, the study can be conducted with other cardiorespiratory conditions such as chronic obstructive pulmonary disease, and coronary artery bypass surgery and intervention measures such as cardiopulmonary rehabilitation and prognostic score in perioperative screening. Further studies can be repeated with large samples to establish the cutoff values and minimal clinical interpretable differences for the 3MRWT. This may indeed help the clinicians for preoperative screening, rehabilitation perspectives, and postoperative prognosis. Further studies are needed to know the validity and reliability of the 3MRWT in various clinical populations.

  Conclusion 

This study demonstrated that newly developed 3MRWT is valid over routinely available 6MWT. It may provide a higher functional stress in a shorter duration than later in valvular replacement patients in assessing the maximal functional capacity during discharge. It could be used to eliciting hemodynamic stress in perioperative valve replacement patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
  [Table 1], [Table 2]