国家经济命脉 meaning in Chinese

economic life line of the country

For a long time the traditional industrial enterprises have been the pillar of the national economics lifeline
长期以来，传统工业企业是国家经济命脉的支柱。
So maybe we can make such a further metaphor , the headwaters of the reservoir are the enterprises , especially the small and medium enterprises . as the minor water heads , they are the crucial sources for the economy of the whole country
在此基础上是否可以进一步扩展， “水库”的上游是企业，特别是作为各“细微水脉”的中小企业则是整个国家经济命脉之重要源泉。