Demographic parameters of patients with > 4MET and < 4MET
Patients with < 4MET had a significant higher incidence of diabetes mellitus (p = 0.0002), peripheral artery occlusive disease (p < 0.0001), history of smoking (p = 0.003), adipositas (p = 0.03) and chronic obstructive pulmonary disease (p = 0.05). Furthermore, this group had a tendency to more previous cardiovascular interventions, otherwise the two cohorts were comparable (Table 2).
Table 2
Demographic parameters
|
METS
|
p
|
> 4 (n = 220)
|
< 4 (n = 56)
|
Age (median) (Interquartile range)
|
71.8 (65,0–77,3)
|
71.0 (64.5–76.5)
|
0,80
|
Gender (female)
|
30 (13.6%)
|
13 (23.2%)
|
0,09
|
Localisation
|
|
|
0.21
|
• Infrarenal
|
131 (59.6%)
|
38 (67.9%)
|
|
• Juxtarenal
|
61 (27.7%)
|
16 (28.6%)
|
|
• Thoracoabdominal
|
13 (5.9%)
|
0 (0%)
|
|
• Thoracic
|
15 (6.8%)
|
2 (3.6%)
|
|
Nicotine
|
125 (56.8%)
|
44 (78.6%)
|
0,003
|
Arterial hypertension
|
145 (65.9%)
|
39 (69.6%)
|
0,75
|
Diabetes (*on insuline)
|
13 (5.9%); (*6 (2.7%))
|
11 (19.6%); (*6 (10.7%))
|
0,0002
|
Adipositas
|
31 (14.1%)
|
31 (55.4%)
|
0,03
|
Dyslipidemia
|
105 (47.7%)
|
15 (26.8%)
|
0,37
|
Coronary artery disease
|
69 (31.4%)
|
19 (33.9%)
|
0,75
|
COPD (chronic obstructive pulmonary disease)
|
43 (19.5%)
|
18 (32.1%)
|
0,05
|
Renal insufficiency
|
24 (10.9%)
|
9 (16.1%)
|
0,36
|
Stroke
|
19 (8.6%)
|
6 (10.7%)
|
0,53
|
Myocardial infarction
|
22 (10%)
|
10 (17.9%)
|
0,11
|
Peripheral arterial occlusive disease
|
38 (17.3%)
|
25 (44.6%)
|
< 0,0001
|
Previous cardiovascular interventions*
(*various procedures in
one patient possible)
|
72 (32.7%)
|
23(41.1%)
|
0,24
|
• Aortocoronary bypass operation
|
28 (12,7%)
|
8 (14.3%)
|
0,76
|
• Coronary stenting
|
27 (12.3%)
|
7 (12.5%)
|
0,96
|
• Valve operation
|
12 (5.5%)
|
2 (3.6%)
|
0,57
|
• Aortic operation/procedure
|
8 (3.6%)
|
5 (8.9%)
|
0,09
|
• Peripheral vascular operation
|
6 (2.7%)
|
4 (7.1%)
|
0,11
|
Emergency / urgent procedures
|
17 (7.7%) / 15 (6.8%)
|
3 (5.4%) / 5 (8.9%)
|
0,54/ 0,59
|
Excluded: 20 patients with unclear METS status; 19 emergencies, 1 urgent operation |
Follow up and survival
From May 2009 till March 2016, 296 patients underwent open or endovascular aortic repair and were divided into four main groups depending on infrarenal, juxta- and pararenal, thoraco-abdominal and thoracic pathology (Table 1). Out of these, 276 patients had a preoperative statement of their functional capacity in MET. Twenty operations were done under emergency or urgent conditions. The median follow-up of the patients’ cohort was 10.8 months. Mean survival of the whole cohort with recorded MET status (n = 276) was 74 months. There was no significant difference between patients with a functional capacity of more than 4 MET (220 patients, mean survival: 74.5 months) and patients with less than 4 MET (56 patients, mean survival: 65.4 months) (p = 0.64) (Fig. 1). The mean survival of the infrarenal cohort (n = 169) was 74.3 months with no significant differences between both MET groups (> 4 MET: 131 patients, mean survival 75.5 months; <4MET: 38 patients, mean survival 63.6 months. p = 0.35). The infrarenal cohort was subdivided in four groups based on the operative technique (open or endovascular) and the preoperative MET status (> 4 or < 4 MET). The Kaplan Meier survival of all four subgroups shows no significant differences concerning the mean survival (p = 0.82) (Fig. 2). The subgroup after open surgical technique with less than 4 MET had the lowest mean survival of 38.8 months.
Perioperative complications and reoperations
In 46 patients with > 4METS (20.9%) perioperative complications occurred compared to the group with < 4METS with 18 patients (32.1%). In the group with unknown MET status (n = 20), the majority developed perioperative complications (65% = 13 patients). Four patients (20%) of this group had reoperations. By excluding these patients with unknown MET status, there was no significant difference between patients with 4 > MET and 4 < MET (p = 0.075), but a slight tendency for more complications in patients with < 4METS (32.1% vs 20.9%).
Fifty-seven complications occurred in the 46 patients with > 4MET. Of these 57 complications, 21 (36.8%) led to major reoperations and 11 (19.3%) to minor reoperations. Compared to the complications in the patient group with < 4MET, there was no significant difference regarding the number of major and minor reoperations (p = 0.89 major; p = 0.43 minor) (Table 3).
Table 3) Perioperative complications
|
|
METS
|
|
|
>4 (n = 220)
|
<4 (n = 56)
|
p
|
Perioperative complications
|
|
|
|
Number of patients with complications
|
46 (20.9%)
|
18 (32.1%)
|
0,07
|
All complications (various complications per one patient included)
|
57 (100%)
|
26 (100%)
|
|
• Minor re-operation
|
11 (19.3%)
|
7 (26.9%)
|
0,43
|
• Major re-operation
|
21 (36.8%)
|
10 (38.5%)
|
0,89
|
• No re-operation
|
25 (43.9%)
|
9 (34.6%)
|
0,43
|
Minor: Limb compartment, Pacemaker implantation, Perm-Cath implantation, Wound revision, Drainage |
Major: Abdominal compartment, bleeding with re-laparotomy/re-thoracotomy, graft occlusion, intestinal resection |
Further complications: renal insufficiency/dialysis, rhythm, endoleak (without therapy), bronchial infection, delirium |
MET and late postoperative cardiovascular interventions
Sixteen percent of all patients irrespective of their functional capacity underwent a cardiovascular intervention after the initial hospitalization during the follow-up period (36 patients with > 4MET; 9 patients with < 4MET). Four of twenty patients with an unknown status of MET underwent postoperative cardiovascular interventions (20%). There was no significant difference among these groups (p = 0.91).
MET and major events (stroke or myocardial infarction) after hospitalization
In the group of patients with > 4MET (220 patients), 3.6% (8 patients) developed a myocardial infarction (MI) after hospitalization and 1.8% (4 patients) had a stroke, which results in a cumulative rate of 5.5% (12 patients) with major events after hospitalization. Compared to the group with < 4MET (56 patients), 8.9% (5 patients) suffered a myocardial infarction and no stroke. Only one patient (5%) had a myocardial infarction in the group with unknown MET status (20 patients). Although, there was no significant difference among the groups (p = 0.40), there might be a slight tendency to more myocardial infarction in the group with < 4MET.
MET and in-hospital death
Thirteen patients died, which results in an in-hospital mortality of 4.4% for all procedures and approaches. In the infrarenal group of 182 patients the in-hospital mortality was 3.8%. Seven patients died, two from cardiovascular events, five from other events. Six of these seven patients were operated conventionally by laparotomy, one received an endovascular prosthesis. In-hospital mortality after juxtarenal approach (n = 84) was 4.8% (2 cardiovascular deaths, 2 other deaths). During follow up, there were 8 deaths in the infrarenal (3 cardiovascular and 5 other) and 2 deaths (both cardiovascular) in the juxtarenal group.
In the thoraco-abdominal (n = 13) and thoracic approach group (n = 17) respectively, one patient died from cardiovascular cause, which results in an in-hospital mortality of 7.7% and 5.9%. During follow up, there were no further deaths in both groups.
In the subgroup analysis of infrarenal patients there were no significant differences concerning in-hospital mortality with regard to preoperative MET status (p = 0.99).
Sensitivity of MET status for perioperative cardiovascular risk assessment
One hundred patients with > 4MET received concomitant cardiac assessment before the operation. In two of these patients the result of the assessment was unknown, while 81 showed normal results and 17 had pathological findings (= 98 patients with > 4MET and cardiac assessment). In the group with < 4MET, 48 patients underwent preoperative cardiac work-up. Out of these 36 had normal results, whereas 12 showed pathological results in stress echocardiography or coronary angiography. Thus, sensitivity of functional capacity assessment with MET was 41% with a low positive predictive value of 25%. In the group of > 4MET with preoperative cardiac work-up (n = 98), 17 patients showed pathological results. In 7 (7%) out of these this had therapeutic consequences. In the group of < 4MET (n = 48), 4 (8.3%) out of 12 patients received preoperative interventions as a result of abnormal findings. Thus, the risk to miss a potential need for cardiac optimization in patients > 4MET was 7% (Fig. 3).