Conservative Surgical Treatment Methods of Aortic Pathology - Research Paper Example

We would like to thank the department of heart and chest surgery, University that participated in this survey, and all the patients who gave their consent to participate. We would like to thank the Elsevier Language Editing Services for providing language help.

Background: There has been marked increase in the number of cases with aortic pathology, which resulted in the search for conservative surgical treatment methods. Improved treatment and reduced incidence of perioperative complications have been reported with new mini-sternotomy techniques as compared with full sternotomy in hemisternotomy. However, the benefits of mini-sternotomy over sternotomy in median sternotomy are yet to be established in the current literature. The aim of this study was to analyze and compare the outcomes of aortic valve replacement through full sternotomy and mini-sternotomy in median sternotomy.

Methods: We retrospectively evaluated 140 patients who underwent an isolated replacement of the aortic valve via full sternotomy or mini-sternotomy in a university hospital between 2011 and 2016. Of these, 70 (50%) patients underwent mini-sternotomy (mini-sternotomy group) and 70 (50%) underwent full sternotomy (control group).

Results: No statistical difference in operative time was noted (p=0.856). Mini-sternotomy had longer cross clamp (88.720.7 vs. 80.324.6 min, p=0.007) and bypass (144.029.9 vs. 132.944.9 min, r=0.049) times, lower incidence of repeated cardioplegia (0 (0.0%) vs. 3 (4.3%), p=0.042), less ventilation time (9.71.7 vs. 11.71.4 h, p<0.001), shorter hospital stay (18.31.4 vs. 21.91.3 days, p=0.012), less 24-h chest tube drainage (256.228.6 vs. 407.340.37 mL, p<0.001), fewer correction of coagulopathy (p<0.001), fewer patients receiving adrenalin (5.71 vs. 30.0%, p<0.001), fewer patients receiving morphine (90.00 vs. 98.57%, p=0.029), and better cosmetic results (p<0.001). Moreover, the number of patients without complaints at 1 year after the operation was significantly greater in the mini-sternotomy group (p=0.002).

Conclusions: Mini-sternotomy has a number of advantages compared with full sternotomy; thus, mini-sternotomy could be a better approach for aortic valve replacement.

Keywords: Aortic valve replacement; Mini-sternotomy; Sternotomy

Introduction

Recently, the number of cases with aortic pathology has increased markedly, which resulted in the search for conservative surgical treatment methods (1-3). Consequently, new minimally invasive approaches (e.g., upper and lower mini-sternotomy; V-shaped, Z-shaped, T-shaped, J- shaped sternotomy; and other types of mini-sternotomy) were introduced (4-6). New mini-sternotomy techniques have improved the treatment and reduced the incidence of perioperative complications compared with full sternotomy (2-6).

Currently, a number of studies comparing short-term and long-term results of full sternotomy and minimally invasive techniques have been conducted for hemisternotomy (7-9). Minimally invasive approaches reduced the amount of blood loss, probability of infection, and hospitalization duration; improved the cosmetic results; and accelerated patient recovery (10-13).

Despite the numerous advantages inherent to minimally invasive techniques, some authors noted several negative effects, such as longer aortic cross-clamp and cardiopulmonary bypass times (12-14, 20-24), which could in turn influence surgery performance and could be an unfavorable factor for patients of advanced age (25-27).

In this study, we present our experience with mini-sternotomy in median sternotomy. The purpose of our study is to compare the results for aortic valve replacement operations by means of median sternotomy and minimal invasion (Mini-sternotomy).

Materials and methods

This is a retrospective study of patients who underwent isolated aortic valve replacement through sternotomy or mini-sternotomy. All operations were performed between 2011 and 2016 in university hospital in Lithuania (Vilnius University Hospital Santaros Klinikos). From 2011 to 2016, 426 cardiac interventions were performed, of which 70 (16.4%) were minimal access surgeries and 356 (83.6%) were interventions by means of longitudinal sternotomy. Permission to conduct the study was obtained from the Vilnius Regional Biomedical Research Ethics Committee (Vilniaus Regioninio Biomedicininiu Tyrimu Etikos Komiteto) Nr. 158200-14-715-235.

The patients were selected according to age, sex, Body Mass Index, etiology of the underlying disease, diagnosis, New York Heart Association (NYHA) evaluation, and echocardiographic parameters. To reduce selection bias, we used propensity score matching. Both the mini-sternotomy and full sternotomy (control) groups had 70 patients each.

Patients requiring reoperation and procedures such as coronary artery bypass grafting, surgery of mitral or other valves, ascending aorta replacement, atrial fibrillation ablation, or aortic valve plasty were excluded from the study.

Statistical analysis

Statistical processing of the data was performed by variation statistics methods using IBM SPSS 20.0(IBM Corp, NY, USA), STATISTICA 12 (Stat soft, Tulsa, OK, USA). Data are represented as absolute numbers and percentages for categorical variables and as mean values and standard deviations for continuous variables. Dichotomous variables were compared using Fisher's exact test and the chi-square test. The T-test was used to compare continuous variables. Kaplan-Meier analysis and the log-rank test were employed to assess survival.

Results

The number of males was higher than that of females in full sternotomy and mini-sternotomy (54.2% and 60% respectively). Overall, the sternotomy patients were slightly older with a mean age of 61.411.9 years than the mini-sternotomy patients with a mean of 60.811.4 years (p=0.155). Table 1 illustrates the significant preoperative characteristics for the minimal invasive- and full sternotomy patients. The characteristics between the groups were similar before surgery; however, EuroSCORE II >3% occurred more frequently in the sternotomy group than in the mini-sternotomy group (11.4% versus 2.9%, p = 0.049). Analysis of comorbidity showed that the mini-sternotomy group had more patients with hypertension than the sternotomy group (22 versus 10, p=0.016). Chronic obstructive pulmonary disease (COPD) was significantly more frequent in patients with minimally invasive access (4 (5.7%), p=0.042); COPD was not observed in the full sternotomy group.

Table1 Preoperative patients characteristics and morbidities

Indicator Full sternotomy

N=70 Mini-sternotomy

N=70 r

Age, years, mean SD 61.411.9 60.811.4 0.155

Male, n (%) 193(54.2) 42(60.0) 0.374

Height (cm), mean SD 170.19.0 170.841.05 0.247

Body weight (kg), mean SD 81.01.6 82.31.82 0.886

BMI (kg/m2), mean SD 27.94.5 27.704.39 0.536

Diagnosis, n (%)

Aortic stenosis

Aortic regurgitation

Combined 45(64.3)

13(18.6)

12(17.1) 51(72.9)

12(17.1)

7(10.0) 0.275

0.825

0.217

Etiology of the disease, n (%)

Senile degeneration

Annular expansion

Mitral valve

Infective endocarditis 53(75.7)

12(17.4)

0(0.0)

5(7.1) 53(75.7)

13(18.6)

1(1.4)

3(4.3) 1.000

0.825

0.316

0.466

EuroSCORE II <1%, n (%)

EuroSCORE II 1-3%, n (%)

EuroSCORE II >3%, n (%)

Mean EuroSCORE II (%), meanSD 20(28.6)

42(60.0)

8(11.4)

1.670.07 24(34.3)

44(62.9)

2(2.9)

1.480.45 0.466

0.728

0.049

0.256

NYHA functional class, n (%)

II

III

IV 6(8.6)

64(91.4)

0(0.0) 12(17.1)

57(81.4)

1(1.4) 0.130

0.084

0.316

International normalized ratio, meanSD 1.070.15 1.070.04 0.200

Creatinine clearance (mL/min)

<50, n (%)

5085, n (%)

>85, n (%)

Mean creatinine levels (mmol/L), meanSD 36(51.4)

31(44.3)

3(4.3)

80.9320.60 41(58.6)

27(38.6)

2(2.86)

82.14215.84 0.396

0.493

0.649

0.425

Highest creatinine level (mmol/L), meanSD 100.2660.92 92.6525.07 0.325

Diabetes mellitus, n(%) 5(7.1) 11(15.7) 0.111

COPD, n (%) 0(0.0) 4(5.7) 0.042

Hypertension, n (%) 10(16.0) 22(31.4) 0.016

Peripheral vascular disease, n(%) 1(1.4) 0(0.0) 0.316

Stroke, n (%) 2(2.9) 0(0.0) 0.154

Coronary artery disease, n (%) 1(1.4) 3(4.3) 0.310

Anticoagulation therapy 1 week before surgery, n(%) 0(0.0) 2(2.9) 0.316

Pacemaker, n (%) 2(2.8) 5(7.1) 0.245

PG max (mm Hg), mean SD 60.6235.50 64.9040.80 0.650

PG mean (mm Hg), mean SD 43.6522.50 51.7923.05 0.682

Table 2 presents the intraoperative characteristics of both groups. Mini-sternotomy required significantly longer aortic cross-clamping time (8 min longer) than that required for sternotomy (p=0.007). Mini-sternotomy also required longer cardiopulmonary bypass time, which lasted for almost 12 min longer than that in full sternotomy (p=0.049). Repeated cardioplegia was performed in 3 (4.3%) patients from the sternotomy group, but was not applied to the mini-sternotomy group (p=0.042).

Table 2 Intraoperative characteristics of both groups

Indicator Full sternotomy

N=70 Mini-sternotomy

N=70 r

Aortic cross-clamping time (min), mean SD 80.324.6 88.720.7 0.007

Cardiopulmonary bypass time (min), mean SD 132.944.9 144.029.9 0.049

Cardioplegia during surgery, n (%)

Retrograde

Coronary mouth

Retrograde + coronary mouth 4 (5.7)

30 (42.9)

36 (51.4) 0 (0.0)

70 (100)

0 (0.0) 0.042

<0.001

<0.001

Repeated cardioplegia, n (%) 3 (4.3) 0 (0.0) 0.042

Aortotomy type, n (%)

Transverse aortotomy

Hockey stick aortotomy 6 (8.6)

64 (91.4) 32 (45.7)

38 (54.3) <0.001

<0.001

Valve type, n (%)

Biological

Mechanical 163(45.8)

193(54.2) 60 (85.7)

10 (14.3) <0.001

<0.001

ECMO, n (%) 0 (0.0) 1 (1.4) 0.428

IABP, n (%) 0 (0.0) 0 (0.0) --

IABP, intra-aortic balloon pump; ECMO, extracorporeal membrane oxygenation

*p<0.05, differences between groups are significant

Postoperative statistics (Table 3) show that mini-sternotomy had a few advantages over full sternotomy. The duration of mechanical ventilation was significantly shorter during mini-sternotomy than during full sternotomy (9.71.7 h versus 11.71.4 h, p=0.001). The amount of blood flowing through the drain for 24 h in mini-sternotomy was almost 1.5 times more than that in full sternotomy (p<0.001). The total duration of hospitalization in the full sternotomy group was almost 4 days longer than that of the mini-sternotomy group (p=0.012). Fourteen patients (20%) in the full sternotomy group underwent correction of coagulopathy; no correction of coagulopathy was performed in the mini-sternotomy group (p<0.001). Moreover, evaluation of drug therapy for hemodynamic support showed that adrenalin is used significantly more often in the full sternotomy group than in the mini-sternotomy group (30.0% versus 5.71%, p< 0.001). Evaluation of the use of pain medication showed that morphine is used significantly more often during full sternotomy than during mini-sternotomy (98.57% versus 90.00%, p=0.029). In the mini-sternotomy group, non-steroidal anti-inflammatory drugs were used significantly more often (98.57 vs. 78.57%, p<0.001). The group differences of all the characteristics were statistically insignificant.

Table 3 Postoperative outcomes

Indicator Full sternotomy

N=70 Mini-sternotomy

N=70 r

Ventilation time (h), mean SD 11.71.4 9.71.7 <0.001

24-h chest tube drainage (mL), mean SD 407.2540.37 256.228.6 <0.001

Patients with correction of coagulopathy, n (%) 14(20.0) 0(0.0) <0.001

Hospital stay (days), mean SD 21.91.9 18.31.9 0.012

Stroke, n (%) 0(0.0) 0(0.0) ---

The number of patients treated with Adrenaline, n (%)

Morphine, n (%)

NSAIDs (other than paracetamol), n (%) 21(30.0)

69(98.57)

69(98.57) 4(5.71)

63(90.0)

55...